Thrombin time

Thrombin time (TT) is a blood test that measures the time it takes for a clot to form in the plasma of a blood sample containing anticoagulant, after an excess of thrombin has been added. It is used to diagnose blood coagulation disorders and to assess the effectiveness of fibrinolytic therapy.

Procedure

The thrombin time test is performed by adding thrombin to a sample of plasma. The time it takes for a clot to form is then measured. The normal range for thrombin time is usually around 14-16 seconds, but this can vary depending on the laboratory that analyzes the sample.

Clinical significance

Thrombin time is used in the diagnosis of various coagulation disorders. It is particularly useful in the diagnosis of disseminated intravascular coagulation (DIC), a condition characterized by systemic activation of blood coagulation, which results in clot formation and bleeding. Thrombin time can also be used to monitor the effectiveness of treatment with heparin, a commonly used anticoagulant.

Limitations

While thrombin time is a useful test, it has some limitations. It is not specific for any particular coagulation disorder and can be affected by a variety of factors, including the presence of heparin or fibrin degradation products in the sample. Therefore, it is usually used in conjunction with other coagulation tests to diagnose and monitor coagulation disorders.

See also

• Prothrombin time
• Partial thromboplastin time
• International normalized ratio
• Bleeding time
• Platelet function testing