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OUTLINE
Abnormal Clot
Retraction
indicates on abnormal platelet numbers, abnormal glycoprotein amount or
structure, abnormal platelet signaling, abnormal fibrinogen levels, or
abnormal fibrinogen structure
PROTOCOL
- Use either the whole blood or platelet-rich
plasma
(PRP)
- To obtain PRP, collect 500 µl of blood on
50
µl of ACD
- Add 600 µl of PBS, centrifuge once at
10ƒC,
1200 rpm ( Joan, GR 412)
- In Glass Centrifuge Tube add 100 µl of
PRP and
160µl of clot retraction buffer, and 50µl of working
solution of thrombin (8 U/mL) and 5-10 µL of erythrocytes (for
visualization). Vortex briefly.
- Place the Dead End Glass Rod (use Pasteur
Pipette) to the bottom of the tube. Place the tube at 37ƒC.
Check the CLOT FORMATION (appearance) and RETRACTION. Measure the
volume of remained solution after clot retraction, notice the color of
solution, take digital picture.
SOLUTIONS
- Clot Retraction Buffer: 400 mL of PBS x1 + 10
mL of
PBS-MgCl2 (MgCm2=4g/L) + 10 mL PBS-CaCl2 (CaCl2= 5.3 g/L)
- Working Solution of Thrombin = 7 µl of
Thrombin
(1250U/mL) + 1 mL of Clot Retraction Buffer
ADDITIONAL INFO
The Clot Retraction
Test
may be used for screening of new anti-platelet drugs,
anti-platelet-antibodies, or unexplained bleeding-problems. This test
does not indicate exactly what is the problem but shows the direction
to look for it.
REFERENCES
- Platelet Protocols.
Research and Clinical
Laboratory
Procedures. McCabe White M. and Jennings L.K. Academic Press, 1999
- Azam M. et al, Molecular
Cellular Biology,
March
2001, p. 2213-2230, Vol. 21, No. 6
- Hodivala-Dilke KM et al,
Beta3-integrin-deficient
mice are a model for Glanzmann thrombasthenia showing placental defects
and reduced survival. J. Clin. Investig. 103:229-238
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