Thromboplastin

Thromboplastin is a substance present in blood, tissues, and platelets necessary for the clotting of blood. It is a complex enzyme that is released from damaged cells, especially blood platelets, and that converts prothrombin into thrombin in the presence of certain ions, particularly calcium.

Function

Thromboplastin plays a crucial role in the blood coagulation process. It is released by platelets and damaged tissue cells to initiate the coagulation cascade, which results in the formation of a blood clot. Thromboplastin acts as a catalyst in the conversion of prothrombin to thrombin, a key enzyme in the coagulation process.

Clinical Significance

The amount of thromboplastin and its rate of production can be affected by various medical conditions. For instance, a deficiency in thromboplastin can lead to hemophilia, a disorder that results in excessive bleeding. On the other hand, an overproduction of thromboplastin can lead to thrombosis, a condition where blood clots form inappropriately within blood vessels.

Measurement

The prothrombin time (PT) test is a common laboratory procedure used to measure the amount of thromboplastin in the blood. This test is often used to monitor patients who are taking anticoagulant medications, such as warfarin, to ensure that their blood is clotting at the appropriate rate.

See Also

• Blood clot
• Coagulation
• Hemophilia
• Thrombosis
• Prothrombin time

References

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