1102. Thrombin time (TT)

Thrombin time (TT) is a laboratory test that evaluates the final stage of blood clotting, namely the conversion of fibrinogen to fibrin under the action of thrombin. The test helps identify clotting disorders associated with fibrinogen deficiency or dysfunction, as well as the presence of thrombin inhibitors.

Thrombin time should be tested in conjunction with other coagulation parameters, such as the 282 test or a coagulogram.

Thrombin time is a sensitive coagulation test that determines the time it takes for a fibrin clot to form in blood plasma after the addition of thrombin. It is used to assess the third phase of blood coagulation – fibrin formation – and to detect natural and pathological anticoagulants.

This test depends solely on the concentration of fibrinogen and the presence of thrombin inhibitors, in particular:

• Antithrombin III;
• Heparin;
• Paraproteins (e.g., in myeloma).

When?

• If a final coagulation disorder is suspected.
• During preparation for surgery.
• As part of a comprehensive coagulation profile.
• To evaluate anticoagulant therapy.
• To assess the risk of developing DIC syndrome (in severe infectious diseases, acute and chronic leukemia, pregnancy and childbirth complications, autoimmune diseases), diagnosis, and treatment monitoring.

For whom?

• Patients with hepatological diseases.
• For patients diagnosing quantitative (hypo(a)fibrinogenemia) and qualitative disorders (acquired dysfibrinogenemia in liver diseases, paraneoplastic dysfibrinogenemia, autoimmune diseases, and hereditary dysfibrinogenemia) as causes of increased bleeding (metro-, menorrhagia, nosebleeds, soft tissue hematomas, bleeding in the postpartum or postoperative period) or a tendency to thrombosis (phlebothrombosis, pulmonary embolism, arterial thrombosis), as well as in cases of a combination of both conditions.
• For patients as part of a comprehensive examination to establish the causes of habitual miscarriage, the development of pre- and eclampsia, and premature detachment of a normally located placenta (PND).

• Venous blood

In order to exclude factors that may affect the test results, we recommend to follow the preparation rules: