What is Clot Retraction Time?

Clot Retraction time is directly proportional to the platelet count and inversely proportional to the fibrinogen concentration. It helps in detecting the ability of the blood to clot formation. The process by which a blood clot becomes smaller and draws the edges of a broken blood vessel together and which involves the shortening of fibrin threads and the squeezing out of excess serum.

Clot retraction is the "shrinking" of a blood clot over a number of days. In so doing, the edges of the blood vessel wall at the point of injury are slowly brought together again to repair the damage. Clot retraction is dependent on the release of multiple coagulation factors from platelets trapped in the fibrin mesh of the clot. Thus, failure to retract can be a sign of thrombocytopenia or a rare condition called thrombasthenia.

How is clot retraction done?

Clot retraction is a process driven by outside-in signaling by platelet integrin ?IIb?3 that results in the contraction of the fibrin mesh. The contraction of the fibrin clot results in the blood clot becoming smaller and excess fluid is extruded.

What is a clot retraction test used for?

The clot retraction study measures the time taken for a platelet plug to undergo this last step, which indicates overall platelet function.

What is the normal clotting time?

It is affected by calcium ion levels and many diseases. The normal value of clotting time is 2-8 minutes. For the measurement of clotting time by test tube method, blood is placed in a glass test tube and kept at 37° C. The required time is measured for the blood to clot.

What are the 3 stages of blood clotting?

1. Constriction of the blood vessel.
2. Formation of a temporary “platelet plug."
3. Activation of the coagulation cascade.
4. Formation of “fibrin plug” or the final clot.