GB2175691A - Bleeding time measurement - Google Patents
Bleeding time measurement Download PDFInfo
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- GB2175691A GB2175691A GB08510629A GB8510629A GB2175691A GB 2175691 A GB2175691 A GB 2175691A GB 08510629 A GB08510629 A GB 08510629A GB 8510629 A GB8510629 A GB 8510629A GB 2175691 A GB2175691 A GB 2175691A
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- filter
- blood
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- diameter
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- 230000000740 bleeding effect Effects 0.000 title description 16
- 238000005259 measurement Methods 0.000 title description 3
- 210000004369 blood Anatomy 0.000 claims abstract description 62
- 239000008280 blood Substances 0.000 claims abstract description 60
- 239000002245 particle Substances 0.000 claims abstract description 6
- 238000012360 testing method Methods 0.000 claims description 16
- 238000000034 method Methods 0.000 claims description 9
- 239000003365 glass fiber Substances 0.000 claims description 3
- 206010053567 Coagulopathies Diseases 0.000 claims description 2
- 239000003146 anticoagulant agent Substances 0.000 claims description 2
- 229940127219 anticoagulant drug Drugs 0.000 claims description 2
- 230000035602 clotting Effects 0.000 claims description 2
- 238000010998 test method Methods 0.000 claims description 2
- 208000032843 Hemorrhage Diseases 0.000 description 15
- 208000034158 bleeding Diseases 0.000 description 15
- 230000000903 blocking effect Effects 0.000 description 15
- 230000000717 retained effect Effects 0.000 description 11
- 230000000750 progressive effect Effects 0.000 description 7
- 230000001186 cumulative effect Effects 0.000 description 5
- 238000000338 in vitro Methods 0.000 description 5
- KCXVZYZYPLLWCC-UHFFFAOYSA-N EDTA Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O KCXVZYZYPLLWCC-UHFFFAOYSA-N 0.000 description 4
- 229960001484 edetic acid Drugs 0.000 description 4
- HTTJABKRGRZYRN-UHFFFAOYSA-N Heparin Chemical compound OC1C(NC(=O)C)C(O)OC(COS(O)(=O)=O)C1OC1C(OS(O)(=O)=O)C(O)C(OC2C(C(OS(O)(=O)=O)C(OC3C(C(O)C(O)C(O3)C(O)=O)OS(O)(=O)=O)C(CO)O2)NS(O)(=O)=O)C(C(O)=O)O1 HTTJABKRGRZYRN-UHFFFAOYSA-N 0.000 description 3
- 208000027276 Von Willebrand disease Diseases 0.000 description 3
- 230000002159 abnormal effect Effects 0.000 description 3
- 210000004027 cell Anatomy 0.000 description 3
- 229960002897 heparin Drugs 0.000 description 3
- 229920000669 heparin Polymers 0.000 description 3
- 230000014759 maintenance of location Effects 0.000 description 3
- 210000004623 platelet-rich plasma Anatomy 0.000 description 3
- 208000012137 von Willebrand disease (hereditary or acquired) Diseases 0.000 description 3
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 2
- 229910052791 calcium Inorganic materials 0.000 description 2
- 239000011575 calcium Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 108010039209 Blood Coagulation Factors Proteins 0.000 description 1
- 102000015081 Blood Coagulation Factors Human genes 0.000 description 1
- 208000032544 Cicatrix Diseases 0.000 description 1
- KRKNYBCHXYNGOX-UHFFFAOYSA-K Citrate Chemical compound [O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O KRKNYBCHXYNGOX-UHFFFAOYSA-K 0.000 description 1
- 229920000742 Cotton Polymers 0.000 description 1
- 229920004934 Dacron® Polymers 0.000 description 1
- 108010054218 Factor VIII Proteins 0.000 description 1
- 102000001690 Factor VIII Human genes 0.000 description 1
- 206010062713 Haemorrhagic diathesis Diseases 0.000 description 1
- 206010021245 Idiopathic thrombocytopenic purpura Diseases 0.000 description 1
- 208000007536 Thrombosis Diseases 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 201000003710 autoimmune thrombocytopenic purpura Diseases 0.000 description 1
- 239000011324 bead Substances 0.000 description 1
- 239000003114 blood coagulation factor Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 208000020832 chronic kidney disease Diseases 0.000 description 1
- 229940001468 citrate Drugs 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000000502 dialysis Methods 0.000 description 1
- 238000000635 electron micrograph Methods 0.000 description 1
- 208000028208 end stage renal disease Diseases 0.000 description 1
- 201000000523 end stage renal failure Diseases 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 229960000301 factor viii Drugs 0.000 description 1
- 210000000245 forearm Anatomy 0.000 description 1
- 238000013467 fragmentation Methods 0.000 description 1
- 238000006062 fragmentation reaction Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 230000002008 hemorrhagic effect Effects 0.000 description 1
- 230000023597 hemostasis Effects 0.000 description 1
- 238000001727 in vivo Methods 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 208000017169 kidney disease Diseases 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000001575 pathological effect Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 239000005020 polyethylene terephthalate Substances 0.000 description 1
- 230000007425 progressive decline Effects 0.000 description 1
- 231100000241 scar Toxicity 0.000 description 1
- 230000037387 scars Effects 0.000 description 1
- 238000012216 screening Methods 0.000 description 1
- 238000010008 shearing Methods 0.000 description 1
- 206010043554 thrombocytopenia Diseases 0.000 description 1
- 230000003582 thrombocytopenic effect Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- 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
- G01N33/4905—Determining clotting time of blood
Landscapes
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Biomedical Technology (AREA)
- Chemical & Material Sciences (AREA)
- Hematology (AREA)
- Physics & Mathematics (AREA)
- Food Science & Technology (AREA)
- Molecular Biology (AREA)
- Urology & Nephrology (AREA)
- Ecology (AREA)
- Biophysics (AREA)
- Medicinal Chemistry (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analysing Biological Materials (AREA)
Abstract
Blood is tested by passing it under pressure through a filter 1 and measuring the amount of blood passing through as a function of time. The filter 1 is made of fibres passing in all directions and bonded together to define tortuous channels of different sizes permitting the passage through the filter of particles up to 10 mu m in diameter. <IMAGE>
Description
SPECIFICATION
Bleeding time measurement
This invention relates to a method and apparatus for testing blood in order to obtain a measurement of bleeding time.
The conventional method of measuring bleeding time consists in making, usually, two or three controlled superficial cuts on the forearm after applying a sphygmomanometer to the upper arm and inflating it to 40 mm Hg.
This test is only moderately reliable; it hurts a little and often leaves small scars. It is not usually possible to make many repeated observations, e.g. to monitor treatment.
The conventional test gives an "in vivo" bleeding time which is dependent on the global interaction between the cut vessel wall and the blood, in which the platelets play a major part.
For some time there have been tentative studies involving pushing blood through small holes and observing whether the platelets are "activated" and block the hole. "In vitro" bleeding time tests have been developed in which blood is passed through a filter. In particular, such a test is described in S. Uchiyama et al., "Clinical Evaluation of a New Test of Hemostasis: The Filter Bleeding Time", Thrombosis Research 34, pp. 397-405,
1984. The method is based on the progressive decrease in drop rate of 5 ml of citrated whole venous blood through a filter of low porosity woven "Dacron" (Trade Mark for polyester) ("Meadox"-a Trade Mark for a graft material) under a pressure of 150 mm
Hg as platelet aggregates occlude the filter.
The filter bleeding time (FBT) is defined as the time until the drop interval exceeds 1 minute.
If an in vitro bleeding time test is abnormal in all of most people with a haemorrhagic diathese, it should be of great general use. It could be used as a screening procedure before operations; as part of the routine investigation of people with a haemorrhagic diathesis; and to monitor the effect of treatment, for example when a patient is bleeding and a specific clotting factor is being transfused.
However, the test according to Uchiyama et al has some drawbacks. The blood used is citrated, thereby removing calcium and decreasing the value of the test. The pressure of
150 mm Hg tends to cause fragmentation of the red cells and the platelets.
The present invention is based on research into the behaviour of blood when passed through various filters under pressure. As a result of trials with many different filters, the inventor has determined that the structure of the filter is critical to the value of the in vitro bleeding time test.
The invention provides a method of testing blood comprising passing blood under pressure through a filter and measuring the amount of blood passing through as a function of time, in which the filter is made of fibres passing in all directions and bonded together to define tortuous channels of different sizes through the filter, permitting the passage of particles of up to 10 ,um diameter through the filter.
The fibres are preferably glass fibres and are preferably resin-bonded. The fibres constituting the filter preferably are of different diameters; the diameter may be up to 5 ,um, more preferably up to 4 ,us., and may be as small as 0.1 ,um.
The use of such a filter does not require the high pressure of 150 mm Hg in the Uchiyama et al. test.
If the pressure is too low (e.g. 5 mm Hg) there may be no progressive slowing of the amount of blood passing through the filter.
Preferably, the pressure is at least 20 mm Hg.
The preferred pressure range is 40 to 100 mm Hg.
Clotting of the blood may be inhibited by the addition of an anticoagulant such as heparin.
The invention also provides apparatus for testing blood, comprising a filter, means for passing blood through the filter under pressure, and means for continuously measuring the amount of blood passing through the filter, in which the filter is made of fibres passing in all directions and bonded together to define tortuous channels of different sizes through the filter, permitting the passage of particles of up to 10 Crm diameter through the filter.
The apparatus preferably includes a filter holder, and a syringe connectable to the filter holder and having an inlet for air under pressure.
The invention will be described further, by way of example, with reference to the accompanying drawings, in which:
Figure 1 schematically shows apparatus for measuring bleeding time;
Figures 2 to 4 are graphs of cumulative drop counts versus time, in use of the apparatus;
Figure 5 is a graph of the decrease in drop rate versus the percentage of platelets retained by the filter in the apparatus;
Figure 6 is a graph of cumulative drop count versus time, comparing normal blood with blood from patients having von Willebrand's disease; and
Figures 7 and 8 are electron micrographs of the filter structure (magnification: 180 and
1800 respectively).
In the apparatus illustrated the blood to be tested is passed through a filter 1 fitted in a filter holder 2 (e.g. a commercially available filter holder such as one supplied by Nuclepore Ltd.). The filter 1 is cut with an annular knife from a "Pall Filter U/100" (Trade Mark) sheet (supplied by Pall Biomedical Ltd.). The filter is made of resin-bonded glass fibres of different diameters (ranging from about 3.4 ,um down to about 0.11 Am) passing in all directions, substantially randomly (see Figs. 7 and 8); it permits the passage of particles up to 10 ,um in diameter through tortuous passages of different sizes defined between the fibres.
A syringe 3 already containing 0.5 ml air is filled with 2.5 ml of blood 4 and inserted into the filter holder 2, which has already been primed with blood. This unit is then fitted into an air-tight syringe holder (not shown) and air under pressure is delivered from a reservoir 6 via a tap 7 through a hole 8 in the syringe barrel. The air reservoir 6 is supplied by a pump 9 via a tap 11. A the selected air pressure is recorded by a pressure transducer 12.
To start the test, the tap 7 is opened and the air pressure forces blood through the filter 1. immediately below the filter holder 2, drops of blood fall across the path of a light beam emitted by an emitter 13 and received by a sensor 14 connected to a drop counter 16 and a timer 17. The first drop crossing the light beam triggers both the counter 16 and the timer 17. Thereafter, a cumulative drop count is recorded at 1, 5, 10, 15, etc. seconds. The test is taken to be finished when the drop rate falls below 1 drop per 5 seconds or all the blood has passed through the filter.
The blood coming through the filter in a given period, usually between 10 and 30 seconds after the start, is collected in a receiver 18 containing EDTA (ethylene diamine tetraacetic acid) so that the platelet count of the blood collected can be determined. The loss of platelets relative to the unfiltered platelet count can be expressed as a percentage of the unfiltered count (platelet loss %).
The results can be quantitated in a number of ways. For example, the time to blockage can be determined, blockage being defined as occurring when the flow is reduced to 1 drop or less per 5 seconds. The drop count between 5 and 30 seconds can be divided by the drop count between 0 and 5 seconds (which reflects the maximal rate); this drop ratio gives a measure of the slowing, which is usually greatest between 15 and 30 seconds.
Results obtained by the above-described procedure are explained below, with reference to Figs. 2 to 6.
Normal heparinised blood collected within the last 15 min was loaded into the syringe (Fig. 2) 1) At a pressure of 5 mm Hg. There was a slow initial rate of passage through the filter (0.2-1 drop/sec) and the drop rate continued at an almost constant rate for 1-2 min until all the blood had passed through the filter.
Thus there was almost no progressive slowing in the rate.
2) At 40 mm Hg. Initially (0-5 sec) the blood passed rapidly (e.g. 3 drops/sec) through the filter. Thereafter, normally, there was a rapid progressive slowing in the rate of passage, resulting in the complete blocking of the filter by 30-40 sec. This time for complete blocking may be called the "in vitro bleeding time".
3) At 100 mm Hg. Normal blood behaved similarly at 40 and 100 mm Hg. Abnormal blood that showed little slowing at 40 mm Hg was sometimes found to behave more normally at 100 mm Hg, i.e. to show more marked progressive slowing.
Native blood usually produced slightly more rapid blocking than did heparinised blood. Fig.
3 shows graphs of cumulative drop count versus time, for native blood and for blood containing heparin, citrate, and EDTA respectively.
Heparinised platelet rich plasma (PRP) passed through the filter at 40 or 100 mm Hg initially flowed through at a greater rate than whole blood. Thereafter the slowing was very fast, often with complete blocking of the filter by 15-20 sec (Fig. 4).
Platelet retention. The percentage of platelets normally retained in the filter initially was about 50% irrespective of the pressure.
Thereafter: at 5 mm Hg the loss of platelets remained approximately the same; at 40 and 100 mm Hg as blocking proceeded, i.e. between 10 and 30 sec, more platelets were retained-from 70 to 90%. There is a good correlation (r=0.76; n=30) between percentage platelets retained and the rate of blocking (Fig. 5).
The number of platelets retained in the filter.
At 40 mm Hg with blocking occuring at, e.g., 30 sec, about 1 ml of blood had passed through the filter. If the original platelet count was 200 X 109/1 and 80% were retained then the total number of platelets retained in the filter 160 X 106 platelets.
At 5 mm Hg, 2 ml of blood runs through the filter, which does not get blocked. The retention is about 50% and 200 X 106 platelets are retained.
Time and temperature. The passage of heparinised blood through the filter was not affected within the temperature range 20-37"C.
If blood was kept at room temperature for 1 hour, the rate of blockage was either unaffected or slightly shorter.
Reproducibility. Within 1 subject: (heparin blood 40 mm Hg) cumulative drops 5-30 secs=17+3 (n=9).
The effect of the initial platelet count. Provided the initial platelet count was from 70,000 to 5000,000 X 109/1 the rate of blockage was unaffected.
Idiopathic thrombocytopenia (n=2) and blood rendered artifically thrombocytopenic (platelet count less than 70,000 X 109/1) by passage through cotton wool, always ran through the filter with minimal slowing.
Calcium dependence. The progressive slowing and blocking of the filter at 40 or 100 mm Hg, occurred most rapidly in native blood.
Heparinised blood blocked a little more slowly.
Citrated blood shows little progressive slowing and EDTA blood almost none (Fig. 3).
Transit time. Because the structure of the filter is uneven the transit time through different channels must differ. However, the total volume of the channels was calculated from the difference in weight of a dry filter and one filled with water. If 1 ml of blood passes through the filter in 30 sec it can be calculated that the transmit time is approximately 1/1000 sec.
von Willebrand's disease. 12 patients with von Willebrand's disease had been diagnosed in the past by a low Factor Vllle and a low
Factor VIIIR:Ag. All patients had a long bleeding time and poor platelet retention in a glass bead column. Twelve of these bloods were grossly abnormal and did not block the filter.
The 13th showed moderate reduction in the rate of drops emerging and her Factor VIII was higher than the others (Fig. 6).
Renal disease. 12 patients with end stage renal failure on continuous ambulatory peritoneal dialysis (CAPD) have been studied. It is known that this type of patient is at risk of bleeding. Six/12 were repeatedly found not to block the filter, i.e. had long "in vitro bleeding times". Factor VIIIR:AG is high in such patients.
It can be concluded that blocking is due to platelets progressively piling up in the filter channels. No blocking occurs in thrombocytopenia. In pathological bloods in which the rate of blocking is slow, this rate is linearly related to the number of platelets retained in the filter.
It appears that blocking requires stress activation of platelets. Since there was minimal progressive slowing of normal blood passing through the filter at 5 mm Hg, the filter surface itself is not markedly active (but note that some 50% of platelets are retained).
Blocking, however, regularly occurred at 40 mm Hg. This higher pressure might be expected to push blood through the filter faster (which initially it does) and to make it more difficult for platelets to block the channels. In fact the high pressure caused blocking. The only difference from the 5 mm Hg experiment seems to be that at 40 mm Hg there is increased shearing forces exerted on the platelets.
At 5 mm Hg, by 2 minutes 200,000 X 106 platelets were retained but blood still passed freely through the filter. At 40 mm Hg, although the same number of platelets were retained, blocking occurred at 30 sec. Thus it appears that the organisation of the platelets within the filter must differ.
Both the physical effect of red cells in laminar flow and the release of ADP from red cells may influence platelet adhesion in some models. In this model neither mechanism can occur, since heparinised PRP blocks the filter more rapidly than whole blood.
Claims (15)
1. A method of testing blood comprising passing blood under pressure through a filter and measuring the amount of blood passing through as a function of time, in which the filter is made of fibres passing in all directions and bonded together to define tortuous channels of different sizes through the filter, permitting the passage of particles of up to 10 ;im diameter through the filter.
2. A method as claimed in claim 1, in which the pressure is at least 20 mm Hg.
3. A method as claimed in claim 2, in which the pressure is 40 to 100 mm Hg.
4. A method as claimed in any of claims 1 to 3, in which an anticoagulant is added to the blood so as to prevent clotting.
5. Apparatus for testing blood comprising a filter, means for passing blood through the filter under pressure, and means for continuously measuring the amount of blood passing through the filter, in which the filter is made of fibres passing in all directions and bonded together to define tortuous channels of different sizes through the filter, permitting the passage of particles of up to 10 Hm diameter through the filter.
6. Apparatus as claimed in claim 5, in which the fibres are glass fibres.
7. Apparatus as claimed in claim 5 or 6, in which the fibres are resin-bonded.
8. Apparatus as claimed in any of claims 5 to 7, in which the fibres are of different diameters.
9. Apparatus as claimed in any of claims 5 to 8, in which the fibres are up to 5 Xlm in diameter.
10. Apparatus as claimed in claim 9, in which the fibres are up to 4 Am in diameter.
11. Apparatus as claimed in any of claims 5 to 10, in which the fibres are at least 0.1
Am in diameter.
12. Apparatus as claimed in any of claims 5 to 11, including a filter holder, and a syringe coniectable to the filter holder and having an inlet for air under pressure.
13. A method as claimed in any of claims
1 to 4 carried out in apparatus according to any of claims 5 to 12.
14. A method as claimed in claim 1, substantially as described with reference to the accompanying drawings.
15. Apparatus for testing blood, substantially as described with reference to Figs. 1, 7 and 8 of the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08510629A GB2175691A (en) | 1985-04-26 | 1985-04-26 | Bleeding time measurement |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08510629A GB2175691A (en) | 1985-04-26 | 1985-04-26 | Bleeding time measurement |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB8510629D0 GB8510629D0 (en) | 1985-06-05 |
| GB2175691A true GB2175691A (en) | 1986-12-03 |
Family
ID=10578234
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08510629A Withdrawn GB2175691A (en) | 1985-04-26 | 1985-04-26 | Bleeding time measurement |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2175691A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3802221A1 (en) * | 1988-01-26 | 1989-07-27 | Stephan Prof Dr Rer Nat Nees | Apparatus for measuring the activation of cells in a cell suspension, of whole blood cells or of components of blood plasma |
| DE10003093A1 (en) * | 2000-01-25 | 2001-08-02 | Goltz Volker Freiherr Von | Device and method for recording coagulation functions of global, especially primary, hemostasis |
| EP1072879A3 (en) * | 1999-07-26 | 2003-03-05 | Alvise Cortinovis | Method and equipment for the determination of general and capillary viscosity of blood |
| EP2500096A1 (en) | 2011-03-15 | 2012-09-19 | Siemens Healthcare Diagnostics Products GmbH | Method and devices for determining the platelet function in a centrifugal analyser |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1263894A (en) * | 1969-02-14 | 1972-02-16 | Alfred Fleisch | Improvements in fluid agglomeration testing methods and equipment |
| GB1469151A (en) * | 1973-03-13 | 1977-03-30 | Unilever Ltd | Apparatus for determining the degree of platelet aggregation in blood |
| GB2018151A (en) * | 1978-03-06 | 1979-10-17 | Asahi Chemical Ind | Seperation of leukocytes from leukocyte-containing suspension by filtration |
| GB2018149A (en) * | 1978-03-06 | 1979-10-17 | Asahi Chemical Ind | Separation of lymphocytes from lymphocyte-containing suspension by filtration |
-
1985
- 1985-04-26 GB GB08510629A patent/GB2175691A/en not_active Withdrawn
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1263894A (en) * | 1969-02-14 | 1972-02-16 | Alfred Fleisch | Improvements in fluid agglomeration testing methods and equipment |
| GB1469151A (en) * | 1973-03-13 | 1977-03-30 | Unilever Ltd | Apparatus for determining the degree of platelet aggregation in blood |
| GB2018151A (en) * | 1978-03-06 | 1979-10-17 | Asahi Chemical Ind | Seperation of leukocytes from leukocyte-containing suspension by filtration |
| GB2018149A (en) * | 1978-03-06 | 1979-10-17 | Asahi Chemical Ind | Separation of lymphocytes from lymphocyte-containing suspension by filtration |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3802221A1 (en) * | 1988-01-26 | 1989-07-27 | Stephan Prof Dr Rer Nat Nees | Apparatus for measuring the activation of cells in a cell suspension, of whole blood cells or of components of blood plasma |
| EP1072879A3 (en) * | 1999-07-26 | 2003-03-05 | Alvise Cortinovis | Method and equipment for the determination of general and capillary viscosity of blood |
| DE10003093A1 (en) * | 2000-01-25 | 2001-08-02 | Goltz Volker Freiherr Von | Device and method for recording coagulation functions of global, especially primary, hemostasis |
| DE10003093C2 (en) * | 2000-01-25 | 2002-05-16 | Goltz Volker Freiherr Von | Device for investigating properties of the global hemostasis function in whole blood or platelet-rich plasma |
| EP2500096A1 (en) | 2011-03-15 | 2012-09-19 | Siemens Healthcare Diagnostics Products GmbH | Method and devices for determining the platelet function in a centrifugal analyser |
| EP2500095A1 (en) | 2011-03-15 | 2012-09-19 | Siemens Healthcare Diagnostics Products GmbH | Method and devices for determining the platelet function in a centrifugal analyser |
| JP2012194181A (en) * | 2011-03-15 | 2012-10-11 | Siemens Healthcare Diagnostics Products Gmbh | Devices and methods for determining platelet function |
| US9205424B2 (en) | 2011-03-15 | 2015-12-08 | Siemens Healthcare Diagnostics Products Gmbh | Devices for determining the platelet function in a centrifugal analyzer |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8510629D0 (en) | 1985-06-05 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |