CA1307448C - Blood separation device under low pressure conditions - Google Patents
Blood separation device under low pressure conditionsInfo
- Publication number
- CA1307448C CA1307448C CA000550444A CA550444A CA1307448C CA 1307448 C CA1307448 C CA 1307448C CA 000550444 A CA000550444 A CA 000550444A CA 550444 A CA550444 A CA 550444A CA 1307448 C CA1307448 C CA 1307448C
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- Canada
- Prior art keywords
- filter
- plasma
- filters
- capillary
- red blood
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
- B01L3/00—Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
- B01L3/50—Containers for the purpose of retaining a material to be analysed, e.g. test tubes
- B01L3/502—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures
- B01L3/5027—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip
- B01L3/502753—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip characterised by bulk separation arrangements on lab-on-a-chip devices, e.g. for filtration or centrifugation
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D39/00—Filtering material for liquid or gaseous fluids
- B01D39/14—Other self-supporting filtering material ; Other filtering material
- B01D39/20—Other self-supporting filtering material ; Other filtering material of inorganic material, e.g. asbestos paper, metallic filtering material of non-woven wires
- B01D39/2003—Glass or glassy material
- B01D39/2017—Glass or glassy material the material being filamentary or fibrous
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
- B01D61/14—Ultrafiltration; Microfiltration
- B01D61/18—Apparatus therefor
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
- G01N33/483—Physical analysis of biological material
- G01N33/487—Physical analysis of biological material of liquid biological material
- G01N33/49—Blood
- G01N33/491—Blood by separating the blood components
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
- B01D2239/12—Special parameters characterising the filtering material
- B01D2239/1216—Pore size
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
- B01D2239/12—Special parameters characterising the filtering material
- B01D2239/1233—Fibre diameter
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
- B01D2239/12—Special parameters characterising the filtering material
- B01D2239/125—Size distribution
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
- B01L2300/00—Additional constructional details
- B01L2300/06—Auxiliary integrated devices, integrated components
- B01L2300/0681—Filter
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
- B01L2300/00—Additional constructional details
- B01L2300/08—Geometry, shape and general structure
- B01L2300/0809—Geometry, shape and general structure rectangular shaped
- B01L2300/0816—Cards, e.g. flat sample carriers usually with flow in two horizontal directions
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
- B01L2400/00—Moving or stopping fluids
- B01L2400/04—Moving fluids with specific forces or mechanical means
- B01L2400/0403—Moving fluids with specific forces or mechanical means specific forces
- B01L2400/0406—Moving fluids with specific forces or mechanical means specific forces capillary forces
Abstract
BLOOD SEPARATION DEVICE
UNDER LOW PRESSURE CONDITIONS
ABSTRACT OF THE DISCLOSURE
A method for separating plasma from red blood cells and a device utilizing the method in which a low-pressure filter is interposed in a pathway between an inlet port and a reaction area. The sole driving force for the movement of plasma from the filter to the reaction area is capillary force provided by a tubular capillary. The filter is selected from glass microfiber filters of specified characteristics, which can operate in the absence of agglutinins, and filters capable of separating agglutinated red cells from plasma, which require the use of an agglutinin.
UNDER LOW PRESSURE CONDITIONS
ABSTRACT OF THE DISCLOSURE
A method for separating plasma from red blood cells and a device utilizing the method in which a low-pressure filter is interposed in a pathway between an inlet port and a reaction area. The sole driving force for the movement of plasma from the filter to the reaction area is capillary force provided by a tubular capillary. The filter is selected from glass microfiber filters of specified characteristics, which can operate in the absence of agglutinins, and filters capable of separating agglutinated red cells from plasma, which require the use of an agglutinin.
Description
1 3n74~8 BLOOD SEPARATION DEVICE
UNDER LO~ PRESSURE CONDITIONS
This invention relates to techniques and devices for separating plasma from blood by filtration and is particularly directed to filtration at low pressures.
Many diagnostics are carried out in the clinical field utilizing blood as a sample. Although some of these techniques can be carried out on whole blood, it i9 nece~sary ln many instances to utilize serum or plasma as the 3ample in order to obtain an accurate reading. For example, red blood cell~
(erythrocytes) scatter and absorb light and could adversely affect a measurement of either reflected or transmitted light of a diagno~tlc test relying on either of these measurement teohniques.
Traditionally, plasma and serum have been separated from whole blood by centrifuging either before (for plasma) or after (for serum) clotting.
~ q However, centrlfugation i9 time consuming and requires equipment that ls not generally available outside the clinical laboratory. Accordlngly, field testing of numerous blood substances that require serum or plasma 3 is difficult.
A number of techniques have been devised to avoid this problem. The techniques generally utilize a filtering device capable of separating red blood cells from plasma. Numerous materials have been used in the past to form filters. Paper, non^woven fabric, ~heet-like filter material composed of powders or fiber~ such as man^made fibers or glass fibers, and membrane ~ 1 3n7448 filters having suitable pcre sizes have been proposed. For example, U.S. Patent 4,256,693 to Kondo et al. discloses a number of filter materials in a multi~layered integral chemical analysis element for ùse with blood. U.S. Patent 4,477,575 to Vogel et al.
describes a composition and process for permitting the separation of plasma or serum from whole blood utilizing glass fibers in combination with other absorbent layers.
However, these prior art techniques have proven to be unsuitable for use in applications which, because of space and volume restraints, can only utilize a small filter in a device in which a single drop of blood is separated and the plasma is transported through the device solely by means of capillary action. Accordingly, further refine~ent in blood separation techniques is desirable.
A device and a technique for 3eparating red blood cells from plasma are provided ln which a whole blood sample is applled to a filter under conditions in which the driving force for transporting the pla~ma from the exit face of the filter is provided solely by capillary action. Two basic filtering techniques can be used. The first utilizes a glass microfiber filter and does not require the use of red cell agglutinins talthough an agglutinin can be used if desired). The second requires the use of agglutinins but can employ a wide variety of filters.
The glass microfiber filter is selected in terms of particle size retention and thickness to allow plasma to pass more rapidly through the filter than the red blood cells, whose pas~age through the filter is retarded in a manner similar to that which occurs in chromatography columns. Although the red blood cells eventually pass through the filter, sufficient pla~Qma 1 3074~8 has separated and pa~ses by capillary action to a reaction chamber to allow analysis of the analyte present ln the plasma wlthout ~nterference by the red blood cells. When agglutin1ns are u ed, the filter can be any filter capable of separat1ng agglut1nated red blood cells from plasma. However, both techniques are specially adapted for use with small volumes of blood and the low pressures available for use in transporting blood in capillary devices.
In the drawin~s:
Figure 1 shows one embodiment of a filter-containing device of the invention in which a number of examples described below were carried out in which Figure la is an expanded side view, Figure lb is a bottom view of each of the components making up the final devlce, and Figure 1c i9 a top view of the assembled device.
Figure 2 shows an embodiment of a filter^
contalning device of the invention in which two or more plastic formq are welded to form a unitary device having internal chambers in which Figure 2a is a ~ide view and Figure 2b ls a top view of the unitary device after welding.
Flgure 3 is a top view of a filter-containing device of the lnvention having multiple pathways for the passage of separated pla~ma to a reagent chamber.
3 The present lnvention may be carried out in the capillary flow device that is described in detail in Canadian Patent Application Serial No. 514,890, filed July 29, 1987.
The capillary flow device described in this earlier application relies upon capillaries, chambers, and orifices to pump fluids; to control measurement of 1 3074~8 fluids, reaction times, and mixing of reagents; and to determine a detectable 3ignal. The capillaries provide the sole driving force for the movement of liquid through the device.
Although these devices could be utilized with whole blood as previou~ly described, u~e with serum or plasma required separation of red blood cells prior to application of the serum or plasma to the device. The present invention allows application of whole blood directly to these devices or to any other devices which rely on capillary action to provide the driving force for the movement of fluids. By selecting glas~ fiber filters or combinations of agglutinins and either glass or non-glass filters as described in this specification, it is possible to accomplish the desired separation in a very small space with a minimum of cell lysis and without requiring the application of any additional force other than that which Ls supplied by capillary action to move the serum or plasma to a reaction chamber.
One useful aspect of the invention is that separation of red blood cells from plasma can be accomplished uti'izing a single layer of filter material and a small volume of blood. Prior art material~ used for blood separatiorl on a larger scale and/or utilizing multiple-layer filter~ with absorbent layer~ have proven not to be useful under the present conditions for separation.
A key part of a first embodiment of the present device is a glass fiber filter. Particularly suLtable glass fiber filters can be prepared from fibers of borosilicate glass, a material that contains, in addition to silicon dioxide, approximately 10% of boron trioxide as well a~ alkali and alkaline earth oxides and oxides of other metals such as iron, aluminum, and zinc. However, other glas~es can al90 be utilized.
1 30744~
In the production of glass fiber filtering media of the invention, microglass fiber~ are utilized. These are ext~emely fine fibers typically formed by blowing glass through jets as opposed to spun glass material made from drawn gla~s filaments.
Typically, glass fiber filters are prepared from f ibers with diameters between 0.10 and 7.0~m.
However, it i~ important to control the di~tribution of fibers present within this diameter range in order to prepare a glass fiber filter that will be useful in the practice of this invention. A
narrow range of fine fibers with a minimum of large diameter fibers should be used.
A preferred filter will have ~0~, preferably 15 80% or more, of its fibers with diameter3 from 0.10 to 1.23~m and no more than 40%, perferably no more than 20%, with diameters larger than 1.23~m. Filters with essentially all of their fibers having diameters less than 4.00~m are preferred.
On the other hand, the range of flber 9 izes should not be too small within the limits outlined above. A relatively even distribution of diameters in the range of 0.10 to 1.23~m is preferred. An extremely narrow range of fiber diameters (varying over a total range of 0.14~m) has been shown to be incapable of providing correct filter action. Accordingly, it i9 preferred to utilize a distribution of fibers of different diameters 90 that if the 0.10 to 1.23~m range is divided into 2-5 equal divisions, especially 3 or 4 equal divisions, approximately equal numbers of fibers (preferably varying by no more than 10 number percent) will fall into each division ~e.g. a 40, 30, 30;
30,40,30; or 35, 30, 35 number ratio upon division into three ranges of diameter).
Suitable filter sheets can be prepared by applying a mixture of glass fibers in a wet pulp in a paper-making machine. In some cases, a small amount of 1 3074~8 a high-polymer organic binder can be utilized although such binders are not preferred. Typical binders include cellulo~ic or acrylic polymers.
The glass fiber filters used in the pr~ctice of the invention are known as ~epth filters, being composed of irregular]y filtering fibers. Separation is cbtained mainly as a result of mechanical retention of particles. secause of both the irregular size and shape of the fibers, it i9 difficult to give an absolute pore size in such a filter. The filters are generally classified based on retention, which defines the capacity of a filter to remove particles of a given size from an aqueous or other solution.
In selecting glass filters, particle size retention, composition of glass thickness, and density shoùld be taken into consideration in order to provide adequate flltration withoùt hemolysis. A thickness of from 0.5 to O.9mm is preferred, with 0.50 to 0.80 being more preferred, particularly from o.66 to 0.76mm.
Borosilicate and other glas~ that is slightly alkaline ~pH 8.0-11.0, preferably about 9.0-10.5) is preferred. Particle size retention is preferably from about 1.0 to 3.0 microns, more preferably from 1.4 to 3.0 microns, and most preferably from 2.3 to 3.0 microns. A density in the range of from 0.10 to 0.30g/cm3 is preferred, more preferably 0.20g/cm3 to 0.28g/cm3, and most preferably about 0.25g/cm3. Since the approximate density of borosilicate glass is 2.61g/cm3, density can be seen to be a measure of the 3 poro~ity of the glass filter.
The numbers qet forth above are given for borosilicate gla~ filters. Particle ~ize retention and thicknesses would be the ~ame for other types of glass, although the densities would vary proporationately with the density of the respective gla~s selected.
1 ~n7448 A number of commercially prepared glass filters can be utilized in the practice of the invention. F'or example, Micro Filtration Systems (MFS) manufactures three glass fiber filters t'nat can be utilized, identified by the manufacturing number3 GA-200, GB-lOOR and GC-90. GB-100R and GC-90 are utilized as doubled filters in the practice of the present invention. GA-200 has a density of approximately 0.25g/cm3, a thickness of 0.70mm, and a retention size of 2.3 microns when filtering liquids. A double thickness of GB-lOOR has a density of 0.25g/cm3, a thickness of 0.76mm, and a particle size retention of 2.0 micron. A doubled layer of GC-90 has a density of 0.30g/cm3, a thickness of 0.66mm, and a particle size retention of 1.7 micron.
Whatman, Inc., of Clifton, New Jersey, and Schleicher & Schuell, a West Cerman firm with a distribution in Keene, NH, also manufacture a number of different glass microfiber filter~. However, none of the Whatman or Schleicher ~ Schuell filters tested (Whatman GF/C, GF/~, GF/D, GF/F, 934-4H; S~S 3362) has proven to be useful for the purpose of this invention, becau~e of a difference in distribution of sizes of the glass fibers used to manufacture their filters and the resulting effects on red blood cell retention. Other glass fiber filters have also been tested and have been demonstrated not to provide adequate separation: P300, from Nucleopore, Pleasanton, CA (with organic binder?;
HB-5341 and BG-08005, from Hollingsworth ~ Vose, East 30 Walpole, MA; glass fiber filter 111, 121, 131, 141, 151, and 161, from Eaton-Dikeman, Carlisle, PA; and glass fiber filters 85~90F, from by Machery ~ Nagel, Duren, West Germany.
All of the manufactured glass fibers described above (except where noted) are prepared without organic binders. Organic binders tend to reduce pore sizes and otherwise interact with red blood cells as they pass 1 30744~
through filters. Accordingly, binderless gla~s filters are preferred. However, it may be possible to utilize binders in glass filters by selecting densities and fibers sizes that result in equal particle size retention. Furthermore, the strict control described doe~ not need to be ~aintained when utilizing an agglutinin, a~ described below.
A number of different filter types were tested for their ability to effect the separation of plasma from serum using a de~ice whose only motive force is capillary action. Of all the filters tested, binderless glass fiber filter~ having the di~tribution of fiber diameters discussed above gave the best separation. The pressure differential caused by capillary action is apparently significantly lower than that which exists either as a result of the action of gravity on larger samples or as a result of contact of a glass filter of the type described in U.S. Patent 4,477,575, discussed above, with an absorbant pad.
Typically, the available pre~sure is on the order of 2.5 mmHg (34 mm H20) or less.
Binderle~s glass microfiber filters having a volume of approximately 7-10 ~l yielded about 3-4 ~l of plasma when 25 ~1 of blood was applied. When the filter was utilized in a device as shown in Figure l, which i9 described in detail below, plasma appeared at the top of the filter outlet about five second~ after application of whole blood to the filter. Plasma appeared in the well about twelve seconds after 3 application. Although blood cells eventually came through the filter, $ndicating that the blood cells were not being blocked but were being retarded, sufficient plasma had appeared by this time in order to conduct an adequate analysis. Filters of this type have been shown to be useful in filtering blood with hematocrits ranging from 33 to 60%. The ratio of plasma obtained to filter volume can be increased by 1 3~7~8 utillzing lar~er diameter filter while maintain~ng the ~ame f1lter thlckness.
It i~ al~o pos~ible to separate pla~ma from red blood cells in a single drop of biood in a capillary flow device using antibodies to red blood cell~ or other agglutinins in combination with a filter. The filter can be either the glass fiber filters described above (including the filters that do not work in the absence of agg1utinins), paper, or any other type of filter that can filter agglutinated red blood cells. Paper, non-woven fabrics, ~heet-like filter material composed of powders or fibers (such as carbon or glass fibers), and membranes havlng ~uitable pore sizes can all be utilized with antibodies and other agglutlnins. Cellulose fibers, cotton linters, nitrocellulo~e, wood pulp, ~-celluloqe, cellulose nitrate, and cellulose acetate are all suitable for manufacturing acceptable filters and/or membranes.
Agglutln1ns can be present in the filter (in ~oluble form) or can be added to the blood sample prior to filtering tfor example, by having a whole blood sample pass through a capillary or other chamber containing soluble agglutlnins prlor to contacting the fllter). Any chemlcal or blochemical agent capable of causing agglutination of red blood cell can be used, lncluding but not limited to antibodles and lectins.
Such agglutlnins are well known in the field of chemical analysis. Antibodies are preferred agglutinins, particularly for use with undiluted whole blood. However, other soluble agglutinins are alqo satisfactory, both for direct and indirect agglutination of red blood cell~. See, for example, Stites et al., Ba~ic and Clinical Immunology, 4th ed., Lange Medical Publications, Los Altos, CA, (1982), pp 356-359.
1 3~74~8 ~o The antibodies utilized will have binding affinity for a determinant present on the surface of red blood cells. If a ~pecific monoclonal antibody that reacts with a blood antigen is u~ed, such as an antibody that react~ with type-A antigen, it will be neces3ary to match the blood type to the filter being used. Antibodies reactive wit~ any antigen pre3ent on the surface of a red blood cell can be utilized, including but not limited to major histocompatability antigens, cell surface proteins, cell surface carbohydrate~, and cell surface glycoproteins.
It is preferred to utilize a source of mixed antibodie~ that will react with all red blood cells of the specie~ being te~ted. For example, an anti~erum against human red blood cells can be utilized or a mixture of monoclonal antibodies that react with all of the major blood types. Such antibodies are available commercially. For example, an IgG fraction of rabbit anti-human red blood cell antibodies can be obtained from Cooper Biomedical (Westchester, PA). The antibody can be adsorbed onto the surface of the solid used to prepare the filter. In the case of paper filters, antibody can be effectively adsorbed onto paper by merely contacting the paper with an aqueous solution containing the antibody and ttlen removing the water by evaporation. If desired, an antiserum can be applied neat or it may be diluted. There is generally a minimum a~ount of antibody that must be applied to the filter in order for filtration to be effective. If less than the minimum amount i9 present, red blood cells pass too quickly through the filter. However, it is not pos~ible to give a specific amount of an antiserum that must be applied to the filter since different antisera will differ in their ability to bind red blood cells. Accordingly, the optimum amount of antibody is determined empirically. Serial two-fold dilutions of neat antibody-containing solution or "
antiserum are applied to filters in an amount sufflcient to saturate the filter. Efficiency of filtration, lycis of red blood cells, and amount of plasma that passe~s t~ro~lgh the filter when a .standard amount of whole blood is applied are measured. When the IgG fraction of rabbit anti-human red blood cell antibody from Cooper Biomedical was utilized, t~e solution was reconstitlted to give 30 mg/ml of protein and 20 mM phosphate-buffered saline at a pH of 7.3.
The minimum volume of this solution that appeared to be necessary for good filtration was 7.5 ~1 (filter diameter 0.l8 inch utilizing S+S GB003 paper; the filter volume was approximately lO ~l). However, it wa~ not necessary to apply the antibody as a neat solution. Dilutions of 1:10 were still effective in providing efficient filtration. Accordingly, it appears that the volume of solution (10 ~1 in a l:10 dilution) necessary to saturate the filter is more important than providing a high titer of antibody.
When using a filter paper disk 0.180 inch in diameter and a volume of approximately lO ~1, at lea~t 5 ~l, preferably at least 7.5 ~1 of solution appeared to be necessary to saturate the disk and uniformly distribute the antibody throughout the filter. Similar volume ratios (0.5:l and 0.75:l) will be effective for other filter volumes. Uniform distribution of antibody prevents red blood cells from passing through the filter at one location while being trapped in others.
If antibody is added to the sample prior to contact with the filter, it is preferred to carry out the filtration in the presence of an agent capable of ~uppressing hemolysis. Typical suppressing agents include local anaesthetics, such as dibucaine and lidocaine; ~-andrenergic blockers, such as propanolol;
tricyclic antidepressants, such as chlorpromazine and anitriptreine; and 3-hydroxypyridines, such as 3-hydroxy-6-methylpyridine.
12 1 3074~
It may be possible to utilize a filter, with or without antibody, to control the rate of pas~age of plasma or blood (the latter when utilizing a bare paper filter or other material t.hat does not separate red blood cells from plasma). Increasing the amount of antibody on a filter increa~es the time that it takes the plasma front to reach a 3iven location along the capillary path. The filter and the capillary leavin~
the filter each act as a point of resistance to the flow of fluid through the device. In effect, each acts as a valve in a fluid stream. When passage of fluid through the filter meets with more resistance than flow through the caplllary, the system acts as if a first valve is partially closed whi].e a second valve in the fluid stream is open. However, it i~ possible to vary the capillary flow rate so that greater re~istance is present in the capillary. Such a ~ystem acts as if the first valve is open while the ~econd valve is partially closed. By varying filter thickness and density and by ~electing an appropriate capillary diameter, con~iderable control over flow of fluid through the system can be achieved.
The filter as described above has been utilized in the te~t devices descrlbed in the ah~ve 25 Canadian ~at~nt i\pl lication S~rial Numb~r 514,890.
A brief description of these devices is included here to show how the filter is used ln combination with the remainder of an device that utilizes (1) small volumes of blood and (2) capillary action to cause movement of plasma.
A test device utilized in many of the experimental investigations described below is ~et forth in Figure 1. The device was prepared from three plastic pieces approximately the size and ~hape of microocope slides and double^sided tape. Top slide 10 had a hole 12 smaller in diameter than the filter to be 1 3074~8 utilized drilled completely through Qlide 10 and double-sided tape 14, which in the embodiment ~hown does not extend the full length of the top slide but may do so if desired. Middle slide 20 has a hole 22 drilled completely through slide 20 and double-sided t~pe 24, which is applied to the bottom surface of slide 20. Double-side~ tape 24 has a section 26 cut out of the tape to provide capillary channels and chambers when the total device is assembled. Capillary space 26A leads from hole 2Z, which holds the filter, to reaction chamber 26B. An additional caplllary chamber ~6C provides a vent by extending from the reaction chamber to the edge of the tape. Bottom slide 30 is a plain slide that forms a bottom surface of the filter, capillary, and reagent spaces formed by middle slide 20 and tape 24.
The as~embled device 1~ shown in Figure 1C in which dotted llne~ are utilized to show the internal chambers that have been formed. Blood i3 applied at entry port (hole) 12, contacts the filter held ln chamber 22, and ls separated into pla~ma while the red blood cells are retained on the filter. Plasma passes through capillary 26A to reaction chamber 26B while air is vented through capillary vent 26C.
F~gure 2 ~hows a device prepared by welding two or more plastic pieces together to form a unitary device having internal chambers. Numerous embodiments of this de~ice are set forth in C~rladian P~tent ~ ication Serial Number 514,89(), referenced above.
Blood is applied to entry port 42, which is smaller in diameter than chamber 44 which contains filter 46.
Plasma exits the bottom of the fllter into collecting space 48 and is transported by capillary 50 to reaction chamber 52. Vent 54 is provided for exit of air from the device. Ridges 56 may be provlded if desired to aid in the application of blood to the entry port.
Additional capillaries, chambers, vents, and the like 1 ~07~8 l4 ~uch as are described in the incorporated patent applications may be present in device 40 but are ommitted in this Figure for clarity.
A whole blood sample, optionally formulated by addition of anticQagulants or other reagents useful in collection of blood or in undergoing a reaction with the analyte that will be measured, is introduced into the entry port in the receiving unit of a test device. The receiving unit may be a capillary or a larger cha~ber. The receiving unit may be used to measure the particula~ sample volume or may simply serve to receive the sample and direct the sample to the filter. When whole blood contacts the filter, it is separated into its components as described above.
The first component to leave the filter will be plasma or serum, depending on the source of the sample. For the remainder of this discussion the term plasma will be used but ~hould be ùnderstood to represent either plasma or serum.
The filters of the present invention typically comprise a single layer of material rather than multiple layers. They are intended for separation of a single drop of blood, whlch typically has a volume of 30-50 ~1 or less. Accordingly, the volume of the filter is also small, typically in the range of 5 to 20 ~l, in order to avoid absorbing and retaining all of the plasma. Thickness (i.e., measured in the direction of the flow path) 19 preferably in the range of 0.2 -1.5 mm. This range is for all filters and thus i9 somewhat broader than that expressed for glass microfiber filters set forth above. Particle size retention for glass microfiber filters is discussed above. Filters used with agglutinins can be more porous if desired but should retain agglutinated red blood cells, which typically form clumps of cells with apparent diameters from 6^10 ~m for a few cells to greater than 0.1 mm (tO0 ~m) for a large number of ce 119 .
1 30744~
~ he plasma will usually be picked up as it leaves tne filter by one or more capillaries. When blood is applied to the top of a filter, plasma will be collected from the bottom. The side~ of tne filter are 5 in close contact with the walls to prevent red blood cells from passins ar~und the ed3es of the filter.
Optionally, a sealer (usually a polymeric compound) can be used on the sides of the filter. Plasma leavin~ the bottom of the filter can collect in grooves or other spaces between the filter and the surface of the device containing the filter in closest contact with the bottom of the filter. Capillaries will draw plasma off from the collection space or spaces. It will be recognized that the words top, bottom, and sides as used here are relative terms and do not necessarily describe orientation of the filter in relation to the earth's surface. Capillaries will usually have diameters in the range of about 0.01mm to 2mm. The capillaries will vary in length but are generally shorter than 10cm, usually not exceeding about 5cm.
The first capillary may control the rate of flow into the chamber that will usually serve as the reaction chamber. Thus, the capillary may aid in the control of the time with which the plasma is in contact with a reagent contained withln or bound to the walls of the capillary and/or reaction chamber. However, the flow rate of plasma through the filter is limiting in many instances, as described above, ~o that the capillary often i9 transporting plasma as fast as it leaves the filter. The reagent provides a color change or some other means of determining the amount of analyte present in the plasma.
The capillary provides the sole driving force for the movement of liquid through the device after passage of the sample through the filter. The device is normally employed with the capillaries, reaction chambers, and other chambers being oriented in a 1 3[)7448 horlzontal plane so that gravity does not affect the flow rate. The device is employed without anc~llary motive force, such as a pump, gravity, or the like.
Accordin~ly, it i~ essential to select a filter as described herein in order to achieve the separation while allowing capillary forcè to transport plasma through the device. Experimental evidence has demonstrated that the filters described in prior art such as U.S. Pate~ts 4,477,575 and 4,256,693, for separating large volumes of blood aided by ~ravity or which depend on relatively large wicking forces caused by absorbant substances that contact the filter, are ineffective in capillary flow devices of the type utilized in the present invention.
Although the filters described herein can be utilized in the same devices previously described, a preferred configuration for use of devices with glass fiber filters is shown in Figure 3. In this device, whole blood is supplied to an entry port 42' situated above a fllter, designated as a blood separater. A
number of capillaries (50') are arranged at the periphery of the blood separater to transport plasma to the reagent area. The capillaries may be of dlfferent lengths and diameters but are designed to allow plasma to reach the reagent area 52' substantially simultaneou~ly from each capillary. Canadian Application Serial No~5l4~89n describes sizing capillaries to achieve this affect. This design allows for uniform and rapid filling of the reagent area~
3 The invention will now be further described by reference to certain specific examples which are included for purposes of illustration only and are not to be considered limiting of the invention unless otherwise specified.
1'7 EXAMPLE I
Mater1als and Methods Blood. Whole blood in 15 USP units/ml of lithium heparin was used in the following experiments.
Filter disks. The filter dlsks were ~ade from commercialy available filters or other indicated materials by usin~ a 0.180~' puncn.
Welded Cartridges. ABS (acrylamide butadiene styrene) 31ides were welded with the Branson ultrasonic welder at the following settings: pressure ~ 60 psi, weld time - 0.3 sec, hold time ~ 1.5 sec, down speed -3Ø
The essential parts of the device were a filter chamber 33.5 mil thick with a total volume of 16 ~1, a connecting chamber (wider than a normal capillary) 3.5 mm thick, and a reaction chamber with vent hole. The total volume of the connecting chamber and reaction chamber wa~ 8.5 ~1.
Tape Slides. Acetate plastlc strips (6" x 1") were washed ln SparkleenTM301ution, rinsed ln deionized water, and then dried using llnt free towels. The plastic strips were then cut lnto 2.5" x 1" slldes.
Plastic surfaces that contacted plasma were etched in a plasma etcher prior to assembly. The top slide was a clean piece of plastic with a 1" x 0.5" double stlck tape piece stuck to the bottom of the slide. A double-sided, 3.5 mil thick, Scotch brand tape with a pattern that formed capillaries and other lnternal chambers cut 3 out of the tape was stuck to the bottom of what would be the middle slide. A hole was drilled to form the well using a #16 drill (0.1 73n) . A #25 drill was used to make a vent hole in this cover slide. The top strip was stuck to the top of the middle strip with the holes carefully aligned. The filter of choice ls then placed in the well of the middle slide, and a bottom etched slide was stuck to the middle slide~s tape. The filter was flush against the top surface of the bottom slide. The finished slide is shown in Figure 1.
Hemolysis Measurement. The percentage -hemolysis was quantitated by measuring the absorbance of 570nm light by th~ plasma. Absorbance was measured on a Hewlett-Pac~ard ~451 A spectrophotometer. The readings were taken uslng cells having path length~ of approximately 0.01cm. The 0.01 cm path length was in a tape cartridge prepared as described above. The absorbance was converted to percent hemolysis by multiplication of the absorbance by a conversion factor. The peak at 570nm was used for the 0.01cm pathlength cell, and the conversion constant was 42Ø
_ass Fiber Filters. A number of glass fiber fLlters were tested, including GA-200 from Micro Flltration Systems (MFS), which is the filter used in all examples unless another filter i9 specified. GA-200 is a non-woven glass fiber filter containing glass microfibers having typical diameters in the range from 20 0.5 to 1.0 micrometer. The filter i9 0.70 mm thick and retained particles 2.3 ~m in diameter in the liquid phase. The den~ity of the filter is 0.25g/cm3.
Density and thickness values are given prior to the slight compression that took place during the process of fabricating the capillary device.
Results Blood from a patient with sickle cell anemia, blood with artificially produced high and low hematocrits, and normal blood were filtered through the GA-200 filters to determine if blood with an abnormal hematocrit would be effectively filtered.
, 1 307~4~
,9 Blood Type Filtration Time 1* (sec)_Ly3is (%) sickle cell ~ <5 0.80 HCT - 30 + <5 ~~~~
Blood Type Filtration Time 1* Time 2* Volume**
(sec) (sec) (~l) Fresh blood HCT - 48.5 + 4 12.6 2.5 + 5 13 2.5 HCT - 33.0 + 4 ~-9 5 + 5 12.7 5 HCT - 60.0 + 4 13.2 2.5 + 8 27 2.5 + 7 12 2.5 * Time 1 is the time between the addition of the blood tG the filter and the exiting of red blood cells from the filter. Time 2 is the time for the blood to reach the beginning of the reagent well.
Volume ~ the volume of plasma which exited the filter before red blood cells exited the filter.
It i3 evident that the filters are as effective in filtering the abnormal hematocrit blood as they are with normal blood; in fact, lower hematocrit blood appears to flow through the filters faster than normal or high hematocrit blood.
The lower hematocrit blood was more efficiently filtered; that is, more volume plasma per volume of blood exited the filters before the red blood cells~ However, sufficient plasma was separated even in high hematocrit blood to allow plasma testing.
Comparison of Filters from MFS
A variety of filters from Micro Filtration Systems were tested for the ability to filter RBCs from plasma. The nomenclature of the MFS filters is based on their physical properties. The further along the ~econd letter of the name is in the alphabet, the tighter the weave of the filter and the slower the flow through the filter. The numbers in the name correspond to the thickness of the filter; that is, the higher the number, the thicker the filter. Three filters from the group examined proved satisfactory: the GA-200, two GB-lOOR ~tacked on top of each other, and two GC-90 stacked on top of each other.
Filter Time 1 Time 2 Volume ~ Ly3is *
(~ec) (sec) (~1) GA~200 5,0 12.8 4 0.58 GB-100x2 19 32 5 0.95 GC-9Ox2 ---~ 120 S ----* Lysis measured after removal of red blood cells by centrifugation ~ 0.37%
Analyte Recovery After Exposure to Glas~ Fiber Filter The purpose of this experiment was to determine if potential analytes would be ad30rbed by the glas.s fiber filter material. The analytes tested were chole3terol, potassium, and total protein. The experiment was conducted using the following protocol.
1. Serum was obtained from whole blood by drawing the blood into glass Vacu-tainer tubes, transfering the blood to centrifugation tubes, letting the blood stand at room temperature for 20 minutes and then centrifuging for 5 minutes at the blood setting on a TRIAC centrifuge (Clay Adams).
2. The sample was then split, one sample being contacted with the glass fiber filter material and the other being left alone until laboratory analysis.
3. The volume of the filter disks in the tape slides was 12.6 ~1. Assuming 50 ~1 of blood is added to the filter, the ratio of blood volume to filter volume was approximately four. In the experiment, 2 ml of serum was contacted with a 24 mm diameter di~k (depth ~ 0.7mm) with a total volume of 317 ~1. The blood/filter volume ratio waY 2000/317 =
UNDER LO~ PRESSURE CONDITIONS
This invention relates to techniques and devices for separating plasma from blood by filtration and is particularly directed to filtration at low pressures.
Many diagnostics are carried out in the clinical field utilizing blood as a sample. Although some of these techniques can be carried out on whole blood, it i9 nece~sary ln many instances to utilize serum or plasma as the 3ample in order to obtain an accurate reading. For example, red blood cell~
(erythrocytes) scatter and absorb light and could adversely affect a measurement of either reflected or transmitted light of a diagno~tlc test relying on either of these measurement teohniques.
Traditionally, plasma and serum have been separated from whole blood by centrifuging either before (for plasma) or after (for serum) clotting.
~ q However, centrlfugation i9 time consuming and requires equipment that ls not generally available outside the clinical laboratory. Accordlngly, field testing of numerous blood substances that require serum or plasma 3 is difficult.
A number of techniques have been devised to avoid this problem. The techniques generally utilize a filtering device capable of separating red blood cells from plasma. Numerous materials have been used in the past to form filters. Paper, non^woven fabric, ~heet-like filter material composed of powders or fiber~ such as man^made fibers or glass fibers, and membrane ~ 1 3n7448 filters having suitable pcre sizes have been proposed. For example, U.S. Patent 4,256,693 to Kondo et al. discloses a number of filter materials in a multi~layered integral chemical analysis element for ùse with blood. U.S. Patent 4,477,575 to Vogel et al.
describes a composition and process for permitting the separation of plasma or serum from whole blood utilizing glass fibers in combination with other absorbent layers.
However, these prior art techniques have proven to be unsuitable for use in applications which, because of space and volume restraints, can only utilize a small filter in a device in which a single drop of blood is separated and the plasma is transported through the device solely by means of capillary action. Accordingly, further refine~ent in blood separation techniques is desirable.
A device and a technique for 3eparating red blood cells from plasma are provided ln which a whole blood sample is applled to a filter under conditions in which the driving force for transporting the pla~ma from the exit face of the filter is provided solely by capillary action. Two basic filtering techniques can be used. The first utilizes a glass microfiber filter and does not require the use of red cell agglutinins talthough an agglutinin can be used if desired). The second requires the use of agglutinins but can employ a wide variety of filters.
The glass microfiber filter is selected in terms of particle size retention and thickness to allow plasma to pass more rapidly through the filter than the red blood cells, whose pas~age through the filter is retarded in a manner similar to that which occurs in chromatography columns. Although the red blood cells eventually pass through the filter, sufficient pla~Qma 1 3074~8 has separated and pa~ses by capillary action to a reaction chamber to allow analysis of the analyte present ln the plasma wlthout ~nterference by the red blood cells. When agglutin1ns are u ed, the filter can be any filter capable of separat1ng agglut1nated red blood cells from plasma. However, both techniques are specially adapted for use with small volumes of blood and the low pressures available for use in transporting blood in capillary devices.
In the drawin~s:
Figure 1 shows one embodiment of a filter-containing device of the invention in which a number of examples described below were carried out in which Figure la is an expanded side view, Figure lb is a bottom view of each of the components making up the final devlce, and Figure 1c i9 a top view of the assembled device.
Figure 2 shows an embodiment of a filter^
contalning device of the invention in which two or more plastic formq are welded to form a unitary device having internal chambers in which Figure 2a is a ~ide view and Figure 2b ls a top view of the unitary device after welding.
Flgure 3 is a top view of a filter-containing device of the lnvention having multiple pathways for the passage of separated pla~ma to a reagent chamber.
3 The present lnvention may be carried out in the capillary flow device that is described in detail in Canadian Patent Application Serial No. 514,890, filed July 29, 1987.
The capillary flow device described in this earlier application relies upon capillaries, chambers, and orifices to pump fluids; to control measurement of 1 3074~8 fluids, reaction times, and mixing of reagents; and to determine a detectable 3ignal. The capillaries provide the sole driving force for the movement of liquid through the device.
Although these devices could be utilized with whole blood as previou~ly described, u~e with serum or plasma required separation of red blood cells prior to application of the serum or plasma to the device. The present invention allows application of whole blood directly to these devices or to any other devices which rely on capillary action to provide the driving force for the movement of fluids. By selecting glas~ fiber filters or combinations of agglutinins and either glass or non-glass filters as described in this specification, it is possible to accomplish the desired separation in a very small space with a minimum of cell lysis and without requiring the application of any additional force other than that which Ls supplied by capillary action to move the serum or plasma to a reaction chamber.
One useful aspect of the invention is that separation of red blood cells from plasma can be accomplished uti'izing a single layer of filter material and a small volume of blood. Prior art material~ used for blood separatiorl on a larger scale and/or utilizing multiple-layer filter~ with absorbent layer~ have proven not to be useful under the present conditions for separation.
A key part of a first embodiment of the present device is a glass fiber filter. Particularly suLtable glass fiber filters can be prepared from fibers of borosilicate glass, a material that contains, in addition to silicon dioxide, approximately 10% of boron trioxide as well a~ alkali and alkaline earth oxides and oxides of other metals such as iron, aluminum, and zinc. However, other glas~es can al90 be utilized.
1 30744~
In the production of glass fiber filtering media of the invention, microglass fiber~ are utilized. These are ext~emely fine fibers typically formed by blowing glass through jets as opposed to spun glass material made from drawn gla~s filaments.
Typically, glass fiber filters are prepared from f ibers with diameters between 0.10 and 7.0~m.
However, it i~ important to control the di~tribution of fibers present within this diameter range in order to prepare a glass fiber filter that will be useful in the practice of this invention. A
narrow range of fine fibers with a minimum of large diameter fibers should be used.
A preferred filter will have ~0~, preferably 15 80% or more, of its fibers with diameter3 from 0.10 to 1.23~m and no more than 40%, perferably no more than 20%, with diameters larger than 1.23~m. Filters with essentially all of their fibers having diameters less than 4.00~m are preferred.
On the other hand, the range of flber 9 izes should not be too small within the limits outlined above. A relatively even distribution of diameters in the range of 0.10 to 1.23~m is preferred. An extremely narrow range of fiber diameters (varying over a total range of 0.14~m) has been shown to be incapable of providing correct filter action. Accordingly, it i9 preferred to utilize a distribution of fibers of different diameters 90 that if the 0.10 to 1.23~m range is divided into 2-5 equal divisions, especially 3 or 4 equal divisions, approximately equal numbers of fibers (preferably varying by no more than 10 number percent) will fall into each division ~e.g. a 40, 30, 30;
30,40,30; or 35, 30, 35 number ratio upon division into three ranges of diameter).
Suitable filter sheets can be prepared by applying a mixture of glass fibers in a wet pulp in a paper-making machine. In some cases, a small amount of 1 3074~8 a high-polymer organic binder can be utilized although such binders are not preferred. Typical binders include cellulo~ic or acrylic polymers.
The glass fiber filters used in the pr~ctice of the invention are known as ~epth filters, being composed of irregular]y filtering fibers. Separation is cbtained mainly as a result of mechanical retention of particles. secause of both the irregular size and shape of the fibers, it i9 difficult to give an absolute pore size in such a filter. The filters are generally classified based on retention, which defines the capacity of a filter to remove particles of a given size from an aqueous or other solution.
In selecting glass filters, particle size retention, composition of glass thickness, and density shoùld be taken into consideration in order to provide adequate flltration withoùt hemolysis. A thickness of from 0.5 to O.9mm is preferred, with 0.50 to 0.80 being more preferred, particularly from o.66 to 0.76mm.
Borosilicate and other glas~ that is slightly alkaline ~pH 8.0-11.0, preferably about 9.0-10.5) is preferred. Particle size retention is preferably from about 1.0 to 3.0 microns, more preferably from 1.4 to 3.0 microns, and most preferably from 2.3 to 3.0 microns. A density in the range of from 0.10 to 0.30g/cm3 is preferred, more preferably 0.20g/cm3 to 0.28g/cm3, and most preferably about 0.25g/cm3. Since the approximate density of borosilicate glass is 2.61g/cm3, density can be seen to be a measure of the 3 poro~ity of the glass filter.
The numbers qet forth above are given for borosilicate gla~ filters. Particle ~ize retention and thicknesses would be the ~ame for other types of glass, although the densities would vary proporationately with the density of the respective gla~s selected.
1 ~n7448 A number of commercially prepared glass filters can be utilized in the practice of the invention. F'or example, Micro Filtration Systems (MFS) manufactures three glass fiber filters t'nat can be utilized, identified by the manufacturing number3 GA-200, GB-lOOR and GC-90. GB-100R and GC-90 are utilized as doubled filters in the practice of the present invention. GA-200 has a density of approximately 0.25g/cm3, a thickness of 0.70mm, and a retention size of 2.3 microns when filtering liquids. A double thickness of GB-lOOR has a density of 0.25g/cm3, a thickness of 0.76mm, and a particle size retention of 2.0 micron. A doubled layer of GC-90 has a density of 0.30g/cm3, a thickness of 0.66mm, and a particle size retention of 1.7 micron.
Whatman, Inc., of Clifton, New Jersey, and Schleicher & Schuell, a West Cerman firm with a distribution in Keene, NH, also manufacture a number of different glass microfiber filter~. However, none of the Whatman or Schleicher ~ Schuell filters tested (Whatman GF/C, GF/~, GF/D, GF/F, 934-4H; S~S 3362) has proven to be useful for the purpose of this invention, becau~e of a difference in distribution of sizes of the glass fibers used to manufacture their filters and the resulting effects on red blood cell retention. Other glass fiber filters have also been tested and have been demonstrated not to provide adequate separation: P300, from Nucleopore, Pleasanton, CA (with organic binder?;
HB-5341 and BG-08005, from Hollingsworth ~ Vose, East 30 Walpole, MA; glass fiber filter 111, 121, 131, 141, 151, and 161, from Eaton-Dikeman, Carlisle, PA; and glass fiber filters 85~90F, from by Machery ~ Nagel, Duren, West Germany.
All of the manufactured glass fibers described above (except where noted) are prepared without organic binders. Organic binders tend to reduce pore sizes and otherwise interact with red blood cells as they pass 1 30744~
through filters. Accordingly, binderless gla~s filters are preferred. However, it may be possible to utilize binders in glass filters by selecting densities and fibers sizes that result in equal particle size retention. Furthermore, the strict control described doe~ not need to be ~aintained when utilizing an agglutinin, a~ described below.
A number of different filter types were tested for their ability to effect the separation of plasma from serum using a de~ice whose only motive force is capillary action. Of all the filters tested, binderless glass fiber filter~ having the di~tribution of fiber diameters discussed above gave the best separation. The pressure differential caused by capillary action is apparently significantly lower than that which exists either as a result of the action of gravity on larger samples or as a result of contact of a glass filter of the type described in U.S. Patent 4,477,575, discussed above, with an absorbant pad.
Typically, the available pre~sure is on the order of 2.5 mmHg (34 mm H20) or less.
Binderle~s glass microfiber filters having a volume of approximately 7-10 ~l yielded about 3-4 ~l of plasma when 25 ~1 of blood was applied. When the filter was utilized in a device as shown in Figure l, which i9 described in detail below, plasma appeared at the top of the filter outlet about five second~ after application of whole blood to the filter. Plasma appeared in the well about twelve seconds after 3 application. Although blood cells eventually came through the filter, $ndicating that the blood cells were not being blocked but were being retarded, sufficient plasma had appeared by this time in order to conduct an adequate analysis. Filters of this type have been shown to be useful in filtering blood with hematocrits ranging from 33 to 60%. The ratio of plasma obtained to filter volume can be increased by 1 3~7~8 utillzing lar~er diameter filter while maintain~ng the ~ame f1lter thlckness.
It i~ al~o pos~ible to separate pla~ma from red blood cells in a single drop of biood in a capillary flow device using antibodies to red blood cell~ or other agglutinins in combination with a filter. The filter can be either the glass fiber filters described above (including the filters that do not work in the absence of agg1utinins), paper, or any other type of filter that can filter agglutinated red blood cells. Paper, non-woven fabrics, ~heet-like filter material composed of powders or fibers (such as carbon or glass fibers), and membranes havlng ~uitable pore sizes can all be utilized with antibodies and other agglutlnins. Cellulose fibers, cotton linters, nitrocellulo~e, wood pulp, ~-celluloqe, cellulose nitrate, and cellulose acetate are all suitable for manufacturing acceptable filters and/or membranes.
Agglutln1ns can be present in the filter (in ~oluble form) or can be added to the blood sample prior to filtering tfor example, by having a whole blood sample pass through a capillary or other chamber containing soluble agglutlnins prlor to contacting the fllter). Any chemlcal or blochemical agent capable of causing agglutination of red blood cell can be used, lncluding but not limited to antibodles and lectins.
Such agglutlnins are well known in the field of chemical analysis. Antibodies are preferred agglutinins, particularly for use with undiluted whole blood. However, other soluble agglutinins are alqo satisfactory, both for direct and indirect agglutination of red blood cell~. See, for example, Stites et al., Ba~ic and Clinical Immunology, 4th ed., Lange Medical Publications, Los Altos, CA, (1982), pp 356-359.
1 3~74~8 ~o The antibodies utilized will have binding affinity for a determinant present on the surface of red blood cells. If a ~pecific monoclonal antibody that reacts with a blood antigen is u~ed, such as an antibody that react~ with type-A antigen, it will be neces3ary to match the blood type to the filter being used. Antibodies reactive wit~ any antigen pre3ent on the surface of a red blood cell can be utilized, including but not limited to major histocompatability antigens, cell surface proteins, cell surface carbohydrate~, and cell surface glycoproteins.
It is preferred to utilize a source of mixed antibodie~ that will react with all red blood cells of the specie~ being te~ted. For example, an anti~erum against human red blood cells can be utilized or a mixture of monoclonal antibodies that react with all of the major blood types. Such antibodies are available commercially. For example, an IgG fraction of rabbit anti-human red blood cell antibodies can be obtained from Cooper Biomedical (Westchester, PA). The antibody can be adsorbed onto the surface of the solid used to prepare the filter. In the case of paper filters, antibody can be effectively adsorbed onto paper by merely contacting the paper with an aqueous solution containing the antibody and ttlen removing the water by evaporation. If desired, an antiserum can be applied neat or it may be diluted. There is generally a minimum a~ount of antibody that must be applied to the filter in order for filtration to be effective. If less than the minimum amount i9 present, red blood cells pass too quickly through the filter. However, it is not pos~ible to give a specific amount of an antiserum that must be applied to the filter since different antisera will differ in their ability to bind red blood cells. Accordingly, the optimum amount of antibody is determined empirically. Serial two-fold dilutions of neat antibody-containing solution or "
antiserum are applied to filters in an amount sufflcient to saturate the filter. Efficiency of filtration, lycis of red blood cells, and amount of plasma that passe~s t~ro~lgh the filter when a .standard amount of whole blood is applied are measured. When the IgG fraction of rabbit anti-human red blood cell antibody from Cooper Biomedical was utilized, t~e solution was reconstitlted to give 30 mg/ml of protein and 20 mM phosphate-buffered saline at a pH of 7.3.
The minimum volume of this solution that appeared to be necessary for good filtration was 7.5 ~1 (filter diameter 0.l8 inch utilizing S+S GB003 paper; the filter volume was approximately lO ~l). However, it wa~ not necessary to apply the antibody as a neat solution. Dilutions of 1:10 were still effective in providing efficient filtration. Accordingly, it appears that the volume of solution (10 ~1 in a l:10 dilution) necessary to saturate the filter is more important than providing a high titer of antibody.
When using a filter paper disk 0.180 inch in diameter and a volume of approximately lO ~1, at lea~t 5 ~l, preferably at least 7.5 ~1 of solution appeared to be necessary to saturate the disk and uniformly distribute the antibody throughout the filter. Similar volume ratios (0.5:l and 0.75:l) will be effective for other filter volumes. Uniform distribution of antibody prevents red blood cells from passing through the filter at one location while being trapped in others.
If antibody is added to the sample prior to contact with the filter, it is preferred to carry out the filtration in the presence of an agent capable of ~uppressing hemolysis. Typical suppressing agents include local anaesthetics, such as dibucaine and lidocaine; ~-andrenergic blockers, such as propanolol;
tricyclic antidepressants, such as chlorpromazine and anitriptreine; and 3-hydroxypyridines, such as 3-hydroxy-6-methylpyridine.
12 1 3074~
It may be possible to utilize a filter, with or without antibody, to control the rate of pas~age of plasma or blood (the latter when utilizing a bare paper filter or other material t.hat does not separate red blood cells from plasma). Increasing the amount of antibody on a filter increa~es the time that it takes the plasma front to reach a 3iven location along the capillary path. The filter and the capillary leavin~
the filter each act as a point of resistance to the flow of fluid through the device. In effect, each acts as a valve in a fluid stream. When passage of fluid through the filter meets with more resistance than flow through the caplllary, the system acts as if a first valve is partially closed whi].e a second valve in the fluid stream is open. However, it i~ possible to vary the capillary flow rate so that greater re~istance is present in the capillary. Such a ~ystem acts as if the first valve is open while the ~econd valve is partially closed. By varying filter thickness and density and by ~electing an appropriate capillary diameter, con~iderable control over flow of fluid through the system can be achieved.
The filter as described above has been utilized in the te~t devices descrlbed in the ah~ve 25 Canadian ~at~nt i\pl lication S~rial Numb~r 514,890.
A brief description of these devices is included here to show how the filter is used ln combination with the remainder of an device that utilizes (1) small volumes of blood and (2) capillary action to cause movement of plasma.
A test device utilized in many of the experimental investigations described below is ~et forth in Figure 1. The device was prepared from three plastic pieces approximately the size and ~hape of microocope slides and double^sided tape. Top slide 10 had a hole 12 smaller in diameter than the filter to be 1 3074~8 utilized drilled completely through Qlide 10 and double-sided tape 14, which in the embodiment ~hown does not extend the full length of the top slide but may do so if desired. Middle slide 20 has a hole 22 drilled completely through slide 20 and double-sided t~pe 24, which is applied to the bottom surface of slide 20. Double-side~ tape 24 has a section 26 cut out of the tape to provide capillary channels and chambers when the total device is assembled. Capillary space 26A leads from hole 2Z, which holds the filter, to reaction chamber 26B. An additional caplllary chamber ~6C provides a vent by extending from the reaction chamber to the edge of the tape. Bottom slide 30 is a plain slide that forms a bottom surface of the filter, capillary, and reagent spaces formed by middle slide 20 and tape 24.
The as~embled device 1~ shown in Figure 1C in which dotted llne~ are utilized to show the internal chambers that have been formed. Blood i3 applied at entry port (hole) 12, contacts the filter held ln chamber 22, and ls separated into pla~ma while the red blood cells are retained on the filter. Plasma passes through capillary 26A to reaction chamber 26B while air is vented through capillary vent 26C.
F~gure 2 ~hows a device prepared by welding two or more plastic pieces together to form a unitary device having internal chambers. Numerous embodiments of this de~ice are set forth in C~rladian P~tent ~ ication Serial Number 514,89(), referenced above.
Blood is applied to entry port 42, which is smaller in diameter than chamber 44 which contains filter 46.
Plasma exits the bottom of the fllter into collecting space 48 and is transported by capillary 50 to reaction chamber 52. Vent 54 is provided for exit of air from the device. Ridges 56 may be provlded if desired to aid in the application of blood to the entry port.
Additional capillaries, chambers, vents, and the like 1 ~07~8 l4 ~uch as are described in the incorporated patent applications may be present in device 40 but are ommitted in this Figure for clarity.
A whole blood sample, optionally formulated by addition of anticQagulants or other reagents useful in collection of blood or in undergoing a reaction with the analyte that will be measured, is introduced into the entry port in the receiving unit of a test device. The receiving unit may be a capillary or a larger cha~ber. The receiving unit may be used to measure the particula~ sample volume or may simply serve to receive the sample and direct the sample to the filter. When whole blood contacts the filter, it is separated into its components as described above.
The first component to leave the filter will be plasma or serum, depending on the source of the sample. For the remainder of this discussion the term plasma will be used but ~hould be ùnderstood to represent either plasma or serum.
The filters of the present invention typically comprise a single layer of material rather than multiple layers. They are intended for separation of a single drop of blood, whlch typically has a volume of 30-50 ~1 or less. Accordingly, the volume of the filter is also small, typically in the range of 5 to 20 ~l, in order to avoid absorbing and retaining all of the plasma. Thickness (i.e., measured in the direction of the flow path) 19 preferably in the range of 0.2 -1.5 mm. This range is for all filters and thus i9 somewhat broader than that expressed for glass microfiber filters set forth above. Particle size retention for glass microfiber filters is discussed above. Filters used with agglutinins can be more porous if desired but should retain agglutinated red blood cells, which typically form clumps of cells with apparent diameters from 6^10 ~m for a few cells to greater than 0.1 mm (tO0 ~m) for a large number of ce 119 .
1 30744~
~ he plasma will usually be picked up as it leaves tne filter by one or more capillaries. When blood is applied to the top of a filter, plasma will be collected from the bottom. The side~ of tne filter are 5 in close contact with the walls to prevent red blood cells from passins ar~und the ed3es of the filter.
Optionally, a sealer (usually a polymeric compound) can be used on the sides of the filter. Plasma leavin~ the bottom of the filter can collect in grooves or other spaces between the filter and the surface of the device containing the filter in closest contact with the bottom of the filter. Capillaries will draw plasma off from the collection space or spaces. It will be recognized that the words top, bottom, and sides as used here are relative terms and do not necessarily describe orientation of the filter in relation to the earth's surface. Capillaries will usually have diameters in the range of about 0.01mm to 2mm. The capillaries will vary in length but are generally shorter than 10cm, usually not exceeding about 5cm.
The first capillary may control the rate of flow into the chamber that will usually serve as the reaction chamber. Thus, the capillary may aid in the control of the time with which the plasma is in contact with a reagent contained withln or bound to the walls of the capillary and/or reaction chamber. However, the flow rate of plasma through the filter is limiting in many instances, as described above, ~o that the capillary often i9 transporting plasma as fast as it leaves the filter. The reagent provides a color change or some other means of determining the amount of analyte present in the plasma.
The capillary provides the sole driving force for the movement of liquid through the device after passage of the sample through the filter. The device is normally employed with the capillaries, reaction chambers, and other chambers being oriented in a 1 3[)7448 horlzontal plane so that gravity does not affect the flow rate. The device is employed without anc~llary motive force, such as a pump, gravity, or the like.
Accordin~ly, it i~ essential to select a filter as described herein in order to achieve the separation while allowing capillary forcè to transport plasma through the device. Experimental evidence has demonstrated that the filters described in prior art such as U.S. Pate~ts 4,477,575 and 4,256,693, for separating large volumes of blood aided by ~ravity or which depend on relatively large wicking forces caused by absorbant substances that contact the filter, are ineffective in capillary flow devices of the type utilized in the present invention.
Although the filters described herein can be utilized in the same devices previously described, a preferred configuration for use of devices with glass fiber filters is shown in Figure 3. In this device, whole blood is supplied to an entry port 42' situated above a fllter, designated as a blood separater. A
number of capillaries (50') are arranged at the periphery of the blood separater to transport plasma to the reagent area. The capillaries may be of dlfferent lengths and diameters but are designed to allow plasma to reach the reagent area 52' substantially simultaneou~ly from each capillary. Canadian Application Serial No~5l4~89n describes sizing capillaries to achieve this affect. This design allows for uniform and rapid filling of the reagent area~
3 The invention will now be further described by reference to certain specific examples which are included for purposes of illustration only and are not to be considered limiting of the invention unless otherwise specified.
1'7 EXAMPLE I
Mater1als and Methods Blood. Whole blood in 15 USP units/ml of lithium heparin was used in the following experiments.
Filter disks. The filter dlsks were ~ade from commercialy available filters or other indicated materials by usin~ a 0.180~' puncn.
Welded Cartridges. ABS (acrylamide butadiene styrene) 31ides were welded with the Branson ultrasonic welder at the following settings: pressure ~ 60 psi, weld time - 0.3 sec, hold time ~ 1.5 sec, down speed -3Ø
The essential parts of the device were a filter chamber 33.5 mil thick with a total volume of 16 ~1, a connecting chamber (wider than a normal capillary) 3.5 mm thick, and a reaction chamber with vent hole. The total volume of the connecting chamber and reaction chamber wa~ 8.5 ~1.
Tape Slides. Acetate plastlc strips (6" x 1") were washed ln SparkleenTM301ution, rinsed ln deionized water, and then dried using llnt free towels. The plastic strips were then cut lnto 2.5" x 1" slldes.
Plastic surfaces that contacted plasma were etched in a plasma etcher prior to assembly. The top slide was a clean piece of plastic with a 1" x 0.5" double stlck tape piece stuck to the bottom of the slide. A double-sided, 3.5 mil thick, Scotch brand tape with a pattern that formed capillaries and other lnternal chambers cut 3 out of the tape was stuck to the bottom of what would be the middle slide. A hole was drilled to form the well using a #16 drill (0.1 73n) . A #25 drill was used to make a vent hole in this cover slide. The top strip was stuck to the top of the middle strip with the holes carefully aligned. The filter of choice ls then placed in the well of the middle slide, and a bottom etched slide was stuck to the middle slide~s tape. The filter was flush against the top surface of the bottom slide. The finished slide is shown in Figure 1.
Hemolysis Measurement. The percentage -hemolysis was quantitated by measuring the absorbance of 570nm light by th~ plasma. Absorbance was measured on a Hewlett-Pac~ard ~451 A spectrophotometer. The readings were taken uslng cells having path length~ of approximately 0.01cm. The 0.01 cm path length was in a tape cartridge prepared as described above. The absorbance was converted to percent hemolysis by multiplication of the absorbance by a conversion factor. The peak at 570nm was used for the 0.01cm pathlength cell, and the conversion constant was 42Ø
_ass Fiber Filters. A number of glass fiber fLlters were tested, including GA-200 from Micro Flltration Systems (MFS), which is the filter used in all examples unless another filter i9 specified. GA-200 is a non-woven glass fiber filter containing glass microfibers having typical diameters in the range from 20 0.5 to 1.0 micrometer. The filter i9 0.70 mm thick and retained particles 2.3 ~m in diameter in the liquid phase. The den~ity of the filter is 0.25g/cm3.
Density and thickness values are given prior to the slight compression that took place during the process of fabricating the capillary device.
Results Blood from a patient with sickle cell anemia, blood with artificially produced high and low hematocrits, and normal blood were filtered through the GA-200 filters to determine if blood with an abnormal hematocrit would be effectively filtered.
, 1 307~4~
,9 Blood Type Filtration Time 1* (sec)_Ly3is (%) sickle cell ~ <5 0.80 HCT - 30 + <5 ~~~~
Blood Type Filtration Time 1* Time 2* Volume**
(sec) (sec) (~l) Fresh blood HCT - 48.5 + 4 12.6 2.5 + 5 13 2.5 HCT - 33.0 + 4 ~-9 5 + 5 12.7 5 HCT - 60.0 + 4 13.2 2.5 + 8 27 2.5 + 7 12 2.5 * Time 1 is the time between the addition of the blood tG the filter and the exiting of red blood cells from the filter. Time 2 is the time for the blood to reach the beginning of the reagent well.
Volume ~ the volume of plasma which exited the filter before red blood cells exited the filter.
It i3 evident that the filters are as effective in filtering the abnormal hematocrit blood as they are with normal blood; in fact, lower hematocrit blood appears to flow through the filters faster than normal or high hematocrit blood.
The lower hematocrit blood was more efficiently filtered; that is, more volume plasma per volume of blood exited the filters before the red blood cells~ However, sufficient plasma was separated even in high hematocrit blood to allow plasma testing.
Comparison of Filters from MFS
A variety of filters from Micro Filtration Systems were tested for the ability to filter RBCs from plasma. The nomenclature of the MFS filters is based on their physical properties. The further along the ~econd letter of the name is in the alphabet, the tighter the weave of the filter and the slower the flow through the filter. The numbers in the name correspond to the thickness of the filter; that is, the higher the number, the thicker the filter. Three filters from the group examined proved satisfactory: the GA-200, two GB-lOOR ~tacked on top of each other, and two GC-90 stacked on top of each other.
Filter Time 1 Time 2 Volume ~ Ly3is *
(~ec) (sec) (~1) GA~200 5,0 12.8 4 0.58 GB-100x2 19 32 5 0.95 GC-9Ox2 ---~ 120 S ----* Lysis measured after removal of red blood cells by centrifugation ~ 0.37%
Analyte Recovery After Exposure to Glas~ Fiber Filter The purpose of this experiment was to determine if potential analytes would be ad30rbed by the glas.s fiber filter material. The analytes tested were chole3terol, potassium, and total protein. The experiment was conducted using the following protocol.
1. Serum was obtained from whole blood by drawing the blood into glass Vacu-tainer tubes, transfering the blood to centrifugation tubes, letting the blood stand at room temperature for 20 minutes and then centrifuging for 5 minutes at the blood setting on a TRIAC centrifuge (Clay Adams).
2. The sample was then split, one sample being contacted with the glass fiber filter material and the other being left alone until laboratory analysis.
3. The volume of the filter disks in the tape slides was 12.6 ~1. Assuming 50 ~1 of blood is added to the filter, the ratio of blood volume to filter volume was approximately four. In the experiment, 2 ml of serum was contacted with a 24 mm diameter di~k (depth ~ 0.7mm) with a total volume of 317 ~1. The blood/filter volume ratio waY 2000/317 =
6.3 in the experiment.
4. The samples containing filters were vortexed at medium speed for about 20 seconds and then spun in a TRIAC centrifuge for 5 minutes to spin down the glass fibers. The serum was drawn off using a glass pipet. The serum was then analyzed.
Without With Fraction filter filter recovered CHOLESTEROL (mg/dl) 157 158 1.01 1 POTASSIUM (mEq/ml) 4.2 4.2 1.00 TOTAL PROTEIN (gm/dl) 7.2 7.1 0.99 The potassium, total protein, and cholesterol results indicate that there was almost complete recovery of these analytes after contact with the filter.
All publications and patent applications cited in the specification are indicative of the level of skill of those skilled in the art to which this invention pertaing. Each publication i9 individually herein incorporated by reference to the same extent as if each individual publication and patent application had been incorporated by reference individually in the location where cited.
Althou~h the foregolng invention has been de~cribed in some detail by way of illustration and example for purpose~ of clarity and understanding~ it will be obvious to those ~killed in the art that certain changes and modifications may be practiced within the gcope of the appended claims.
4. The samples containing filters were vortexed at medium speed for about 20 seconds and then spun in a TRIAC centrifuge for 5 minutes to spin down the glass fibers. The serum was drawn off using a glass pipet. The serum was then analyzed.
Without With Fraction filter filter recovered CHOLESTEROL (mg/dl) 157 158 1.01 1 POTASSIUM (mEq/ml) 4.2 4.2 1.00 TOTAL PROTEIN (gm/dl) 7.2 7.1 0.99 The potassium, total protein, and cholesterol results indicate that there was almost complete recovery of these analytes after contact with the filter.
All publications and patent applications cited in the specification are indicative of the level of skill of those skilled in the art to which this invention pertaing. Each publication i9 individually herein incorporated by reference to the same extent as if each individual publication and patent application had been incorporated by reference individually in the location where cited.
Althou~h the foregolng invention has been de~cribed in some detail by way of illustration and example for purpose~ of clarity and understanding~ it will be obvious to those ~killed in the art that certain changes and modifications may be practiced within the gcope of the appended claims.
Claims (18)
1. In a clinical diagnostic device in which the driving force for the movement of liquid through a tubular capillary pathway from an inlet port to a reaction area in said device arises from capillary pressure, an improvement which comprises:
a low pressure filter interposed in said pathway, wherein said filter is selected from the group consisting of: (1) glass microfiber filters having a particle size retention in the range of from about 1.0 µm to about 3.0 µm and a flow path in the range of from abut 0.25 to 2.0 mm, and (2) filter capable of separating agglutinated red blood cells from plasma, whereby whole blood applied to said inlet port is separated into plasma and red blood cells by said filter.
a low pressure filter interposed in said pathway, wherein said filter is selected from the group consisting of: (1) glass microfiber filters having a particle size retention in the range of from about 1.0 µm to about 3.0 µm and a flow path in the range of from abut 0.25 to 2.0 mm, and (2) filter capable of separating agglutinated red blood cells from plasma, whereby whole blood applied to said inlet port is separated into plasma and red blood cells by said filter.
2. The device of Claim 1, wherein said filter consists essentially of borosilicate glass fibers.
3. The device of Claim 1, wherein said filter is a binderless glass microfiber filter.
4. The device of Claim 3, wherein said filter has a thickness of 0.5 to 0.9 mm, and a particle size retention of from from about 1.2 to 2.8 µm and comprises glass fibers having diameters essentially all in the range of from 0.10 to 4.0 µm with at least 60% of the fibers having diameters in the range of from 0.10 to 1.23 µm.
5. The device of Claim 4, wherein said device contains no agglutinin for red blood cells.
6. The device of Claim 1, wherein said device further comprises a soluble agglutinin present in said filter or at a point in said pathway prior to contact of said liquid with said filter.
7. The device of Claim 6, wherein said agglutinin is an antibody.
8. The device of Claim 7, wherein said filter comprises glass fibers, paper, or a porous membrane.
9. The device of Claim 7, wherein said filter comprises paper capable of retaining particles having a diameter of 6 µm or greater.
10. A method for separating plasma from red blood cells, which comprises:
applying whole blood to a surface of a low pressure filter, wherein said filter is selected from the group consisting of:
(1) glass microfiber filters having a particle size retention in the range of from about 1.0 µm to about 3.0 µm and a flow path in the range of from about 0.25 to 2.0 mm, and (2) filters capable of separating agglutinated red blood cells from plasma, wherein whole blood is contacted with an agglutinin prior to or concurrently with contacting said filter, in a closed container having an inlet port for applying said blood and an outlet port for collecting said plasma; and withdrawing plasma from contact with a second surface of said filter with a tubular capillary, wherein the force utilized to withdraw said plasma is provided by the capillary action of said capillary.
applying whole blood to a surface of a low pressure filter, wherein said filter is selected from the group consisting of:
(1) glass microfiber filters having a particle size retention in the range of from about 1.0 µm to about 3.0 µm and a flow path in the range of from about 0.25 to 2.0 mm, and (2) filters capable of separating agglutinated red blood cells from plasma, wherein whole blood is contacted with an agglutinin prior to or concurrently with contacting said filter, in a closed container having an inlet port for applying said blood and an outlet port for collecting said plasma; and withdrawing plasma from contact with a second surface of said filter with a tubular capillary, wherein the force utilized to withdraw said plasma is provided by the capillary action of said capillary.
11. The method of Claim 10, wherein said filter is a binderless glass microfiber filter.
12. The method of Claim 11, wherein said filter has a thickness of 0.5 to 0.9 mm, and a particle size retention of from about 1.2 to 2.8 µm and comprises glass fibers having diameters essentially all in the range of from 0.10 to 4.0 µm with at least 60% of the fibers having diameters in the range of from 0.10 to 1.23 µm.
13. The method of Claim 12, wherein said device contains no agglutinin for red blood cells.
14. The method of Claim 10, wherein said method further comprises contacting a soluble agglutinin with said whole blood in said filter or prior to contact of said whole blood with said filter.
15. The method of Claim 14, wherein said agglutinin is an antibody.
16. The method of Claim 15, wherein said filter comprises glass fibers, paper, or a porous membrane.
17. The method of Claim 15, wherein said filter comprises paper capable of retaining particles having a diameter of 6 µm and greater.
18. The method of Claim 10, wherein 50 µl or less of whole blood is applied to said filter.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/924,633 US4753776A (en) | 1986-10-29 | 1986-10-29 | Blood separation device comprising a filter and a capillary flow pathway exiting the filter |
| US924,633 | 1986-10-29 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1307448C true CA1307448C (en) | 1992-09-15 |
Family
ID=25450464
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000550444A Expired - Fee Related CA1307448C (en) | 1986-10-29 | 1987-10-28 | Blood separation device under low pressure conditions |
Country Status (9)
| Country | Link |
|---|---|
| US (1) | US4753776A (en) |
| EP (1) | EP0269240B1 (en) |
| JP (1) | JPH0664051B2 (en) |
| AT (1) | ATE80461T1 (en) |
| AU (1) | AU598312B2 (en) |
| CA (1) | CA1307448C (en) |
| DE (1) | DE3781645T2 (en) |
| ES (1) | ES2035077T3 (en) |
| GR (1) | GR3006417T3 (en) |
Families Citing this family (190)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5135719A (en) * | 1986-10-29 | 1992-08-04 | Biotrack, Inc. | Blood separation device comprising a filter and a capillary flow pathway exiting the filter |
| US4849340A (en) * | 1987-04-03 | 1989-07-18 | Cardiovascular Diagnostics, Inc. | Reaction system element and method for performing prothrombin time assay |
| DE3729001A1 (en) * | 1987-08-31 | 1989-03-09 | Behringwerke Ag | DEVICE AND METHOD FOR SEPARATING BLOOD CELLS FROM BODY LIQUIDS CONTAINING ERYTHROCYTES AND THE USE THEREOF |
| US5208147A (en) * | 1988-07-21 | 1993-05-04 | Radiometer A/S | Means for measuring a characteristic in a sample fluid |
| US4933092A (en) * | 1989-04-07 | 1990-06-12 | Abbott Laboratories | Methods and devices for the separation of plasma or serum from whole blood |
| DE69016813T2 (en) * | 1989-04-07 | 1995-09-07 | Abbott Lab | Method and device for separating plasma or serum from blood. |
| US5064541A (en) * | 1989-04-07 | 1991-11-12 | Abbott Laboratories | Devices and methods for the collection of a predetermined volume of plasma or serum |
| CA2019865A1 (en) * | 1989-07-12 | 1991-01-12 | Yatin B. Thakore | Device and method for separation of fluid components for component testing |
| CA2020029A1 (en) * | 1989-07-12 | 1991-01-13 | Yatin B. Thakore | Device and method for separation of plasma from blood and determination of blood analytes |
| DE69029556T2 (en) * | 1989-10-18 | 1997-05-15 | Fuji Photo Film Co Ltd | Dry analytical element for the quantitative analysis of analytes contained in whole blood |
| US5435970A (en) * | 1989-12-18 | 1995-07-25 | Environmental Diagnostics, Inc. | Device for analysis for constituents in biological fluids |
| DE4015589A1 (en) * | 1990-05-15 | 1991-11-21 | Boehringer Mannheim Gmbh | DEVICE AND THE USE THEREOF FOR SEPARATING PLASMA FROM WHOLE BLOOD |
| US5213964A (en) * | 1990-07-16 | 1993-05-25 | Cholestech Corporation | High-density lipoprotein solid-base precipitation assay method |
| US5147606A (en) * | 1990-08-06 | 1992-09-15 | Miles Inc. | Self-metering fluid analysis device |
| US5208163A (en) * | 1990-08-06 | 1993-05-04 | Miles Inc. | Self-metering fluid analysis device |
| US5139685A (en) * | 1991-03-26 | 1992-08-18 | Gds Technology, Inc. | Blood separation filter assembly and method |
| US5186843A (en) * | 1991-07-22 | 1993-02-16 | Ahlstrom Filtration, Inc. | Blood separation media and method for separating plasma from whole blood |
| FR2688311B1 (en) * | 1991-11-12 | 1995-03-10 | Boy Inst Jacques | PROCESS FOR THE EVIDENCE OF ERYTHROCYTA AGGLUTINATES. |
| US5430542A (en) * | 1992-04-10 | 1995-07-04 | Avox Systems, Inc. | Disposable optical cuvette |
| US5223219A (en) * | 1992-04-10 | 1993-06-29 | Biotrack, Inc. | Analytical cartridge and system for detecting analytes in liquid samples |
| US5726026A (en) * | 1992-05-01 | 1998-03-10 | Trustees Of The University Of Pennsylvania | Mesoscale sample preparation device and systems for determination and processing of analytes |
| US5460974A (en) * | 1992-10-13 | 1995-10-24 | Miles Inc. | Method of assaying whole blood for HDL cholesterol |
| US5660798A (en) * | 1993-04-20 | 1997-08-26 | Actimed Laboratories, Inc. | Apparatus for red blood cell separation |
| US5652148A (en) * | 1993-04-20 | 1997-07-29 | Actimed Laboratories, Inc. | Method and apparatus for red blood cell separation |
| US5766552A (en) * | 1993-04-20 | 1998-06-16 | Actimed Laboratories, Inc. | Apparatus for red blood cell separation |
| US5416026A (en) * | 1993-10-04 | 1995-05-16 | I-Stat Corporation | Method for detecting the change in an analyte due to hemolysis in a fluid sample |
| US5700695A (en) * | 1994-06-30 | 1997-12-23 | Zia Yassinzadeh | Sample collection and manipulation method |
| CA2156226C (en) * | 1994-08-25 | 1999-02-23 | Takayuki Taguchi | Biological fluid analyzing device and method |
| US5589399A (en) * | 1994-10-21 | 1996-12-31 | First Medical, Inc. | System and method for plasma separation and measurement |
| GB9422504D0 (en) | 1994-11-08 | 1995-01-04 | Robertson Patricia M B | Blood testing |
| AU4766896A (en) * | 1995-02-09 | 1996-08-27 | First Medical, Inc. | Peristaltic system and method for plasma separation |
| WO1996035952A1 (en) * | 1995-05-09 | 1996-11-14 | Smithkline Diagnostics, Inc. | Devices and methods for separating cellular components of blood from liquid portion of blood |
| CA2178523C (en) | 1995-06-09 | 2001-08-28 | Tomohiro Kitagawa | Plasma separation filter, plasma separation method using the same and plasma separation apparatus |
| DE69619400T2 (en) * | 1995-06-16 | 2002-09-26 | Univ Washington Seattle | FLAT MICROPRODUCED CROSS-FLOW FILTER FOR LIQUIDS |
| AU704863B2 (en) * | 1995-11-15 | 1999-05-06 | Arkray, Inc. | Device and method for assaying biological components in sample |
| US5981294A (en) * | 1995-11-29 | 1999-11-09 | Metrika, Inc. | Device for blood separation in a diagnostic device |
| US5736404A (en) * | 1995-12-27 | 1998-04-07 | Zia Yassinzadeh | Flow detection appartus and method |
| US5716851A (en) * | 1996-01-16 | 1998-02-10 | Bayer Corporation | Glass/cellulose as protein reagent |
| DE19605582A1 (en) * | 1996-02-15 | 1997-08-21 | Bayer Ag | Graphite nonwovens as functional layers in diagnostic test kits |
| DE69719737T2 (en) * | 1996-03-14 | 2004-02-05 | Spectral Diagnostics Inc., Toronto | IMMUNOASSAY OF WHOLE BLOOD SAMPLES |
| US6391265B1 (en) * | 1996-08-26 | 2002-05-21 | Biosite Diagnostics, Inc. | Devices incorporating filters for filtering fluid samples |
| US5879951A (en) | 1997-01-29 | 1999-03-09 | Smithkline Diagnostics, Inc. | Opposable-element assay device employing unidirectional flow |
| US5939252A (en) * | 1997-05-09 | 1999-08-17 | Lennon; Donald J. | Detachable-element assay device |
| US6177283B1 (en) * | 1997-05-28 | 2001-01-23 | Flexsite Diagnostics, Inc. | Diagnostic assay |
| US6673629B2 (en) | 1998-01-15 | 2004-01-06 | Abbott Laboratories | Neutralization of polycations in a chromatographic device for whole blood use |
| US6391005B1 (en) | 1998-03-30 | 2002-05-21 | Agilent Technologies, Inc. | Apparatus and method for penetration with shaft having a sensor for sensing penetration depth |
| US6471868B1 (en) * | 1998-04-10 | 2002-10-29 | Fuji Photo Film Co., Ltd. | Method of preparing glass fiber filter |
| US20060019404A1 (en) * | 1998-05-06 | 2006-01-26 | Blatt Joel M | Quantitative assay with extended dynamic range |
| US6908770B1 (en) | 1998-07-16 | 2005-06-21 | Board Of Regents, The University Of Texas System | Fluid based analysis of multiple analytes by a sensor array |
| US6410341B1 (en) | 1998-08-06 | 2002-06-25 | Spectral Diagnostics, Inc. | Analytical test device and method for use in medical diagnoses |
| CN1250970C (en) | 1998-08-06 | 2006-04-12 | 光谱诊断公司 | Analytical test device and method |
| US6171870B1 (en) | 1998-08-06 | 2001-01-09 | Spectral Diagnostics, Inc. | Analytical test device and method for use in medical diagnoses |
| US6214629B1 (en) | 1998-08-06 | 2001-04-10 | Spectral Diagnostics, Inc. | Analytical test device and method for use in medical diagnoses |
| US6036659A (en) | 1998-10-09 | 2000-03-14 | Flexsite Diagnostics, Inc. | Collection device for biological samples and methods of use |
| CA2254223A1 (en) | 1998-11-16 | 2000-05-16 | Biophys, Inc. | Device and method for analyzing a biologic sample |
| US7214544B2 (en) * | 1999-03-02 | 2007-05-08 | Qualigen, Inc. | Semi-continuous blood separation using magnetic beads |
| WO2000052446A1 (en) * | 1999-03-02 | 2000-09-08 | Qualigen, Inc. | Methods and apparatus for separation of biological fluids |
| US6225109B1 (en) * | 1999-05-27 | 2001-05-01 | Orchid Biosciences, Inc. | Genetic analysis device |
| US7022517B1 (en) | 1999-07-16 | 2006-04-04 | Board Of Regents, The University Of Texas System | Method and apparatus for the delivery of samples to a chemical sensor array |
| WO2001006253A2 (en) | 1999-07-16 | 2001-01-25 | Board Of Regents, The University Of Texas System | Detection system based on an analyte reactive particle |
| US6319719B1 (en) | 1999-10-28 | 2001-11-20 | Roche Diagnostics Corporation | Capillary hematocrit separation structure and method |
| US6451264B1 (en) | 2000-01-28 | 2002-09-17 | Roche Diagnostics Corporation | Fluid flow control in curved capillary channels |
| US6406672B1 (en) | 2000-01-28 | 2002-06-18 | Roche Diagnostics | Plasma retention structure providing internal flow |
| AU2001238011A1 (en) | 2000-01-31 | 2001-08-07 | Board Of Regents, The University Of Texas System | System for transferring fluid samples through a sensor array |
| US8641644B2 (en) | 2000-11-21 | 2014-02-04 | Sanofi-Aventis Deutschland Gmbh | Blood testing apparatus having a rotatable cartridge with multiple lancing elements and testing means |
| ES2182667B1 (en) * | 2000-12-01 | 2004-06-01 | Universidade Da Coruña | UNIVERSAL METHOD OF EXTRACTION OF HIGH QUALITY DNA. |
| US7435384B2 (en) * | 2001-01-08 | 2008-10-14 | Leonard Fish | Diagnostic instrument with movable electrode mounting member and methods for detecting analytes |
| WO2002061392A2 (en) * | 2001-01-31 | 2002-08-08 | Board Of Regents, The University Of Texas System | Method and apparatus for the confinement of materials in a micromachined chemical sensor array |
| US20030040119A1 (en) * | 2001-04-11 | 2003-02-27 | The Regents Of The University Of Michigan | Separation devices and methods for separating particles |
| US7025774B2 (en) | 2001-06-12 | 2006-04-11 | Pelikan Technologies, Inc. | Tissue penetration device |
| US8337419B2 (en) | 2002-04-19 | 2012-12-25 | Sanofi-Aventis Deutschland Gmbh | Tissue penetration device |
| US9795747B2 (en) | 2010-06-02 | 2017-10-24 | Sanofi-Aventis Deutschland Gmbh | Methods and apparatus for lancet actuation |
| DE60238119D1 (en) | 2001-06-12 | 2010-12-09 | Pelikan Technologies Inc | ELECTRIC ACTUATOR ELEMENT FOR A LANZETTE |
| US7316700B2 (en) | 2001-06-12 | 2008-01-08 | Pelikan Technologies, Inc. | Self optimizing lancing device with adaptation means to temporal variations in cutaneous properties |
| US9427532B2 (en) | 2001-06-12 | 2016-08-30 | Sanofi-Aventis Deutschland Gmbh | Tissue penetration device |
| US7749174B2 (en) | 2001-06-12 | 2010-07-06 | Pelikan Technologies, Inc. | Method and apparatus for lancet launching device intergrated onto a blood-sampling cartridge |
| US9226699B2 (en) | 2002-04-19 | 2016-01-05 | Sanofi-Aventis Deutschland Gmbh | Body fluid sampling module with a continuous compression tissue interface surface |
| US7981056B2 (en) | 2002-04-19 | 2011-07-19 | Pelikan Technologies, Inc. | Methods and apparatus for lancet actuation |
| US7776608B2 (en) | 2001-07-09 | 2010-08-17 | Bayer Healthcare Llc | Volume meter testing device and method of use |
| US6989891B2 (en) | 2001-11-08 | 2006-01-24 | Optiscan Biomedical Corporation | Device and method for in vitro determination of analyte concentrations within body fluids |
| JP4191051B2 (en) * | 2002-02-27 | 2008-12-03 | 三光純薬株式会社 | Plasma or serum separator |
| US7331931B2 (en) | 2002-04-19 | 2008-02-19 | Pelikan Technologies, Inc. | Method and apparatus for penetrating tissue |
| US7713214B2 (en) | 2002-04-19 | 2010-05-11 | Pelikan Technologies, Inc. | Method and apparatus for a multi-use body fluid sampling device with optical analyte sensing |
| US9248267B2 (en) | 2002-04-19 | 2016-02-02 | Sanofi-Aventis Deustchland Gmbh | Tissue penetration device |
| US7229458B2 (en) | 2002-04-19 | 2007-06-12 | Pelikan Technologies, Inc. | Method and apparatus for penetrating tissue |
| US7297122B2 (en) | 2002-04-19 | 2007-11-20 | Pelikan Technologies, Inc. | Method and apparatus for penetrating tissue |
| US8372016B2 (en) | 2002-04-19 | 2013-02-12 | Sanofi-Aventis Deutschland Gmbh | Method and apparatus for body fluid sampling and analyte sensing |
| US8267870B2 (en) | 2002-04-19 | 2012-09-18 | Sanofi-Aventis Deutschland Gmbh | Method and apparatus for body fluid sampling with hybrid actuation |
| US9795334B2 (en) | 2002-04-19 | 2017-10-24 | Sanofi-Aventis Deutschland Gmbh | Method and apparatus for penetrating tissue |
| US7547287B2 (en) | 2002-04-19 | 2009-06-16 | Pelikan Technologies, Inc. | Method and apparatus for penetrating tissue |
| US8579831B2 (en) | 2002-04-19 | 2013-11-12 | Sanofi-Aventis Deutschland Gmbh | Method and apparatus for penetrating tissue |
| US7232451B2 (en) | 2002-04-19 | 2007-06-19 | Pelikan Technologies, Inc. | Method and apparatus for penetrating tissue |
| US7909778B2 (en) | 2002-04-19 | 2011-03-22 | Pelikan Technologies, Inc. | Method and apparatus for penetrating tissue |
| US8702624B2 (en) | 2006-09-29 | 2014-04-22 | Sanofi-Aventis Deutschland Gmbh | Analyte measurement device with a single shot actuator |
| US8221334B2 (en) | 2002-04-19 | 2012-07-17 | Sanofi-Aventis Deutschland Gmbh | Method and apparatus for penetrating tissue |
| US7674232B2 (en) | 2002-04-19 | 2010-03-09 | Pelikan Technologies, Inc. | Method and apparatus for penetrating tissue |
| US7892183B2 (en) | 2002-04-19 | 2011-02-22 | Pelikan Technologies, Inc. | Method and apparatus for body fluid sampling and analyte sensing |
| US7175642B2 (en) | 2002-04-19 | 2007-02-13 | Pelikan Technologies, Inc. | Methods and apparatus for lancet actuation |
| US7901362B2 (en) | 2002-04-19 | 2011-03-08 | Pelikan Technologies, Inc. | Method and apparatus for penetrating tissue |
| US9314194B2 (en) | 2002-04-19 | 2016-04-19 | Sanofi-Aventis Deutschland Gmbh | Tissue penetration device |
| US7976476B2 (en) | 2002-04-19 | 2011-07-12 | Pelikan Technologies, Inc. | Device and method for variable speed lancet |
| US7491178B2 (en) | 2002-04-19 | 2009-02-17 | Pelikan Technologies, Inc. | Method and apparatus for penetrating tissue |
| US8360992B2 (en) | 2002-04-19 | 2013-01-29 | Sanofi-Aventis Deutschland Gmbh | Method and apparatus for penetrating tissue |
| US8784335B2 (en) | 2002-04-19 | 2014-07-22 | Sanofi-Aventis Deutschland Gmbh | Body fluid sampling device with a capacitive sensor |
| US8257967B2 (en) | 2002-04-26 | 2012-09-04 | Board Of Regents, The University Of Texas System | Method and system for the detection of cardiac risk factors |
| US7604775B2 (en) | 2002-08-12 | 2009-10-20 | Bayer Healthcare Llc | Fluid collecting and monitoring device |
| EP1545740A2 (en) * | 2002-09-07 | 2005-06-29 | Arizona Board of Regents | Integrated apparatus and methods for treating liquids |
| JP4210783B2 (en) * | 2002-09-26 | 2009-01-21 | アークレイ株式会社 | Analysis tool |
| JP4262466B2 (en) | 2002-10-28 | 2009-05-13 | アークレイ株式会社 | Analysis tool and analyzer |
| US8574895B2 (en) | 2002-12-30 | 2013-11-05 | Sanofi-Aventis Deutschland Gmbh | Method and apparatus using optical techniques to measure analyte levels |
| WO2004072613A2 (en) * | 2003-02-07 | 2004-08-26 | Board Of Regents, The University Of Texas System | Multi-shell microspheres with integrated chomatographic and detection layers for use in array sensors |
| DE10313201A1 (en) * | 2003-03-21 | 2004-10-07 | Steag Microparts Gmbh | Microstructured separator and microfluidic process for separating liquid components from a liquid containing particles |
| US8153081B2 (en) | 2003-05-29 | 2012-04-10 | Bayer Healthcare Llc | Test sensor and method for manufacturing the same |
| US8262614B2 (en) | 2003-05-30 | 2012-09-11 | Pelikan Technologies, Inc. | Method and apparatus for fluid injection |
| US7850621B2 (en) | 2003-06-06 | 2010-12-14 | Pelikan Technologies, Inc. | Method and apparatus for body fluid sampling and analyte sensing |
| WO2006001797A1 (en) | 2004-06-14 | 2006-01-05 | Pelikan Technologies, Inc. | Low pain penetrating |
| US20060147343A1 (en) * | 2003-06-19 | 2006-07-06 | Arkray, Inc. | Analyzer instrument whith liquid storage portion |
| CN1849514A (en) * | 2003-07-08 | 2006-10-18 | 因韦尔尼斯医药瑞士股份有限公司 | Particle agglutination detection method and device |
| WO2005033659A2 (en) | 2003-09-29 | 2005-04-14 | Pelikan Technologies, Inc. | Method and apparatus for an improved sample capture device |
| EP1680014A4 (en) | 2003-10-14 | 2009-01-21 | Pelikan Technologies Inc | Method and apparatus for a variable user interface |
| AU2004299341A1 (en) * | 2003-12-17 | 2005-06-30 | Inverness Medical Switzerland Gmbh | System |
| JP2007518978A (en) * | 2003-12-24 | 2007-07-12 | ベクトン・ディキンソン・アンド・カンパニー | On-demand tube for plasma |
| US7822454B1 (en) | 2005-01-03 | 2010-10-26 | Pelikan Technologies, Inc. | Fluid sampling device with improved analyte detecting member configuration |
| US8668656B2 (en) | 2003-12-31 | 2014-03-11 | Sanofi-Aventis Deutschland Gmbh | Method and apparatus for improving fluidic flow and sample capture |
| US7150995B2 (en) * | 2004-01-16 | 2006-12-19 | Metrika, Inc. | Methods and systems for point of care bodily fluid analysis |
| US8105849B2 (en) | 2004-02-27 | 2012-01-31 | Board Of Regents, The University Of Texas System | Integration of fluids and reagents into self-contained cartridges containing sensor elements |
| US8101431B2 (en) | 2004-02-27 | 2012-01-24 | Board Of Regents, The University Of Texas System | Integration of fluids and reagents into self-contained cartridges containing sensor elements and reagent delivery systems |
| US20050227370A1 (en) * | 2004-03-08 | 2005-10-13 | Ramel Urs A | Body fluid analyte meter & cartridge system for performing combined general chemical and specific binding assays |
| US20050264815A1 (en) * | 2004-05-07 | 2005-12-01 | Mark Wechsler | Sample element with fringing-reduction capabilities |
| WO2006011062A2 (en) | 2004-05-20 | 2006-02-02 | Albatros Technologies Gmbh & Co. Kg | Printable hydrogel for biosensors |
| EP1765194A4 (en) | 2004-06-03 | 2010-09-29 | Pelikan Technologies Inc | Method and apparatus for a fluid sampling device |
| US9775553B2 (en) | 2004-06-03 | 2017-10-03 | Sanofi-Aventis Deutschland Gmbh | Method and apparatus for a fluid sampling device |
| US7682817B2 (en) * | 2004-12-23 | 2010-03-23 | Kimberly-Clark Worldwide, Inc. | Microfluidic assay devices |
| US8652831B2 (en) | 2004-12-30 | 2014-02-18 | Sanofi-Aventis Deutschland Gmbh | Method and apparatus for analyte measurement test time |
| US8936755B2 (en) | 2005-03-02 | 2015-01-20 | Optiscan Biomedical Corporation | Bodily fluid composition analyzer with disposable cassette |
| US20060235348A1 (en) | 2005-02-14 | 2006-10-19 | Callicoat David N | Method of extracting and analyzing the composition of bodily fluids |
| US7871781B2 (en) * | 2005-05-23 | 2011-01-18 | Phadia Ab | Two step lateral flow assay methods and devices |
| AU2006309284B2 (en) | 2005-05-31 | 2012-08-02 | Board Of Regents, The University Of Texas System | Methods and compositions related to determination and use of white blood cell counts |
| WO2007002480A2 (en) * | 2005-06-24 | 2007-01-04 | Board Of Regents, The University Of Texas System | Systems and methods including self-contained cartridges with detection systems and fluid delivery systems |
| US9561001B2 (en) | 2005-10-06 | 2017-02-07 | Optiscan Biomedical Corporation | Fluid handling cassette system for body fluid analyzer |
| DK2260300T3 (en) * | 2008-03-07 | 2014-01-13 | Advanced Microdevices Pvt Ltd | Method and Device for Particle Removal and Preparation of Drops for Qualitative and Quantitative Bioassay |
| EP2254699A1 (en) * | 2008-03-11 | 2010-12-01 | Koninklijke Philips Electronics N.V. | Filtering apparatus for filtering a fluid |
| FR2929135A1 (en) * | 2008-03-31 | 2009-10-02 | Commissariat Energie Atomique | DEVICE FOR ALIQUOTAGE AND EXEMPTION OF A LIQUID |
| EP2265324B1 (en) | 2008-04-11 | 2015-01-28 | Sanofi-Aventis Deutschland GmbH | Integrated analyte measurement system |
| EP2346604A1 (en) * | 2008-11-13 | 2011-07-27 | Koninklijke Philips Electronics N.V. | Interfacing an inlet to a capillary channel of a microfluidic system |
| US8448499B2 (en) | 2008-12-23 | 2013-05-28 | C A Casyso Ag | Cartridge device for a measuring system for measuring viscoelastic characteristics of a sample liquid, a corresponding measuring system, and a corresponding method |
| US9375169B2 (en) | 2009-01-30 | 2016-06-28 | Sanofi-Aventis Deutschland Gmbh | Cam drive for managing disposable penetrating member actions with a single motor and motor and control system |
| KR101650976B1 (en) * | 2009-02-10 | 2016-08-24 | 호라이즌 테크놀로지, 인코포레이티드 | Solid phase extraction disk and method of manufacture |
| JP5608943B2 (en) * | 2009-03-31 | 2014-10-22 | マイクロ化学技研株式会社 | Plasma separation apparatus and method |
| KR101032691B1 (en) * | 2009-04-17 | 2011-05-06 | (주)디지탈옵틱 | Biosensor for the use of diagnosis that prompt blood separation is possible |
| US9554742B2 (en) | 2009-07-20 | 2017-01-31 | Optiscan Biomedical Corporation | Fluid analysis system |
| EP2456355B1 (en) | 2009-07-20 | 2016-09-14 | Optiscan Biomedical Corporation | Adjustable connector and dead space reduction |
| US9091676B2 (en) | 2010-06-09 | 2015-07-28 | Optiscan Biomedical Corp. | Systems and methods for measuring multiple analytes in a sample |
| WO2011080375A1 (en) * | 2009-12-31 | 2011-07-07 | Valtion Teknillinen Tutkimuskeskus | Tampering detector and method |
| FR2956868B1 (en) | 2010-03-01 | 2014-01-10 | Bio Rad Pasteur | RAPID METHOD FOR DETECTION OF ENZYMES AND MICROORGANISMS |
| US8965476B2 (en) | 2010-04-16 | 2015-02-24 | Sanofi-Aventis Deutschland Gmbh | Tissue penetration device |
| BR112013002064B1 (en) | 2010-07-27 | 2020-11-24 | Northwestern University | DEVICE AND METHODS FOR BLOOD PLASMA FILTERING |
| US8974751B2 (en) * | 2010-07-27 | 2015-03-10 | Boehringer Ingelheim Microparts Gmbh | Apparatus and method for separating components of a sample liquid |
| US8956859B1 (en) | 2010-08-13 | 2015-02-17 | Aviex Technologies Llc | Compositions and methods for determining successful immunization by one or more vaccines |
| US20120143228A1 (en) | 2010-08-30 | 2012-06-07 | Agency For Science Technology And Research | Adhesive structure with stiff protrusions on adhesive surface |
| US9492952B2 (en) | 2010-08-30 | 2016-11-15 | Endo-Surgery, Inc. | Super-hydrophilic structures |
| CN103429349B (en) * | 2011-01-28 | 2015-09-16 | 株式会社日冷生物科学 | The rabbling mechanism of elongated liquid in container, method |
| JP5812469B2 (en) * | 2011-05-18 | 2015-11-11 | 国立大学法人広島大学 | Cell separation chip |
| WO2013006716A1 (en) | 2011-07-06 | 2013-01-10 | Optiscan Biomedical Corporation | Sample cell for fluid analysis system |
| SE536634C2 (en) | 2011-12-09 | 2014-04-15 | Hemcheck Sweden Ab | Device for detecting hemolysis |
| JP6153945B2 (en) | 2011-12-29 | 2017-06-28 | エシコン・インコーポレイテッドＥｔｈｉｃｏｎ， Ｉｎｃｏｒｐｏｒａｔｅｄ | Adhesive structure having tissue penetrating protrusions on the surface |
| US8969648B2 (en) | 2012-04-06 | 2015-03-03 | Ethicon, Inc. | Blood clotting substrate and medical device |
| US8926881B2 (en) | 2012-04-06 | 2015-01-06 | DePuy Synthes Products, LLC | Super-hydrophobic hierarchical structures, method of forming them and medical devices incorporating them |
| US20130288225A1 (en) | 2012-04-27 | 2013-10-31 | Agency For Science Technology And Research | Method for separating whole blood |
| EP2845001B1 (en) | 2012-05-03 | 2016-12-14 | Qualigen, Inc. | Whole blood analytic device and method therefor |
| AU2014241115A1 (en) * | 2013-03-14 | 2015-10-08 | Instrumentation Laboratory Company | Plasma separation from blood using a filtration device and methods thereof |
| KR20150039051A (en) * | 2013-10-01 | 2015-04-09 | 삼성전자주식회사 | Blood filter device separating plasma or serum from blood and the use thereof |
| WO2016025726A1 (en) * | 2014-08-13 | 2016-02-18 | Vivebio, Llc | An analytic membrane array, and plasma separation device incorporating the same |
| US10539579B2 (en) | 2014-09-29 | 2020-01-21 | C A Casyso Gmbh | Blood testing system and method |
| US10288630B2 (en) | 2014-09-29 | 2019-05-14 | C A Casyso Gmbh | Blood testing system and method |
| US10175225B2 (en) | 2014-09-29 | 2019-01-08 | C A Casyso Ag | Blood testing system and method |
| US10816559B2 (en) | 2014-09-29 | 2020-10-27 | Ca Casyso Ag | Blood testing system and method |
| US9897618B2 (en) | 2014-09-29 | 2018-02-20 | C A Casyso Gmbh | Blood testing system |
| WO2016062788A1 (en) | 2014-10-24 | 2016-04-28 | Ait Austrian Institute Of Technology Gmbh | Microfluidic chip for biological analysis |
| USD777343S1 (en) | 2015-05-28 | 2017-01-24 | C A Casyso Ag | Body fluid cartridge device |
| US10295554B2 (en) | 2015-06-29 | 2019-05-21 | C A Casyso Gmbh | Blood testing system and method |
| US10473674B2 (en) | 2016-08-31 | 2019-11-12 | C A Casyso Gmbh | Controlled blood delivery to mixing chamber of a blood testing cartridge |
| JP7083345B2 (en) * | 2016-11-16 | 2022-06-10 | クイデル コーポレーション | Whole blood separator |
| US10843185B2 (en) | 2017-07-12 | 2020-11-24 | Ca Casyso Gmbh | Autoplatelet cartridge device |
| WO2020105270A1 (en) * | 2018-11-19 | 2020-05-28 | 日東電工株式会社 | Blood filter |
| CN109529958A (en) * | 2018-12-14 | 2019-03-29 | 上海艾瑞德生物科技有限公司 | Whole Blood Filtration and blood plasma quantify micro-fluidic chip |
| US10518260B1 (en) * | 2019-05-01 | 2019-12-31 | Nano Discovery, Inc. | Device for separation of plasma or serum from blood cells and methods of using the device |
| US20220288588A1 (en) * | 2019-08-05 | 2022-09-15 | Auer Precision Company, Inc. | Microfluidic passive plasma separation device and method |
| CN110918144A (en) * | 2019-12-13 | 2020-03-27 | 深圳先进技术研究院 | Microfluidic chip and whole blood separation method based on microfluidic chip |
| CN112666088B (en) * | 2021-01-21 | 2023-03-28 | 上海菁一科技有限公司 | Spectrophotometry test method sample treatment test capsule |
Family Cites Families (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2910406A (en) * | 1957-02-13 | 1959-10-27 | Ohio Commw Eng Co | Method for biological particle separation |
| US3464890A (en) * | 1965-03-01 | 1969-09-02 | Brunswick Corp | Method of separating whole blood |
| US3843324A (en) * | 1972-09-13 | 1974-10-22 | Research Corp | Method of cell fractionation and apparatus therefor |
| SE399768B (en) * | 1975-09-29 | 1978-02-27 | Lilja Jan E | CYVETT FOR SAMPLING, MIXING OF, THE SAMPLE WITH A REAGENTS AND DIRECT PERFORMANCE OF, SPECIAL OPTICAL, ANALYSIS OF THE SAMPLE MIXED WITH THE REAGENTS |
| IL51209A (en) * | 1976-03-25 | 1981-02-27 | Baxter Travenol Lab | Blood filter |
| US4310399A (en) * | 1979-07-23 | 1982-01-12 | Eastman Kodak Company | Liquid transport device containing means for delaying capillary flow |
| DE3029579C2 (en) * | 1980-08-05 | 1985-12-12 | Boehringer Mannheim Gmbh, 6800 Mannheim | Method and means for separating plasma or serum from whole blood |
| US4426451A (en) * | 1981-01-28 | 1984-01-17 | Eastman Kodak Company | Multi-zoned reaction vessel having pressure-actuatable control means between zones |
| DE3508427A1 (en) * | 1985-03-09 | 1986-09-11 | Merck Patent Gmbh, 6100 Darmstadt | AGENT AND METHOD FOR SEPARATING PLASMA OR SERUM FROM WHOLE BLOOD |
| US4696797A (en) * | 1985-04-15 | 1987-09-29 | Environmental Diagnostics, Inc. | Suspension liquid separator |
| US4623461A (en) * | 1985-05-31 | 1986-11-18 | Murex Corporation | Transverse flow diagnostic device |
| US4693834A (en) * | 1986-05-05 | 1987-09-15 | Murex Corporation | Transverse flow diagnostic kit |
| US4756884A (en) * | 1985-08-05 | 1988-07-12 | Biotrack, Inc. | Capillary flow device |
-
1986
- 1986-10-29 US US06/924,633 patent/US4753776A/en not_active Expired - Lifetime
-
1987
- 1987-10-16 DE DE8787309171T patent/DE3781645T2/en not_active Expired - Fee Related
- 1987-10-16 EP EP87309171A patent/EP0269240B1/en not_active Expired - Lifetime
- 1987-10-16 ES ES198787309171T patent/ES2035077T3/en not_active Expired - Lifetime
- 1987-10-16 AT AT87309171T patent/ATE80461T1/en not_active IP Right Cessation
- 1987-10-28 AU AU80439/87A patent/AU598312B2/en not_active Ceased
- 1987-10-28 CA CA000550444A patent/CA1307448C/en not_active Expired - Fee Related
- 1987-10-28 JP JP62270484A patent/JPH0664051B2/en not_active Expired - Lifetime
-
1992
- 1992-12-02 GR GR920402781T patent/GR3006417T3/el unknown
Also Published As
| Publication number | Publication date |
|---|---|
| DE3781645D1 (en) | 1992-10-15 |
| EP0269240A1 (en) | 1988-06-01 |
| DE3781645T2 (en) | 1993-02-25 |
| ES2035077T3 (en) | 1993-04-16 |
| JPS63177059A (en) | 1988-07-21 |
| GR3006417T3 (en) | 1993-06-21 |
| AU8043987A (en) | 1988-05-05 |
| AU598312B2 (en) | 1990-06-21 |
| ATE80461T1 (en) | 1992-09-15 |
| JPH0664051B2 (en) | 1994-08-22 |
| EP0269240B1 (en) | 1992-09-09 |
| US4753776A (en) | 1988-06-28 |
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