Thrombin Time
1,270 Kshs | Home Collection Available
Synonyms
Thrombin clotting time (TCT)
Purpose
The Thrombin Clotting Time (TCT) test evaluates how quickly fibrinogen converts into fibrin after the addition of thrombin to citrated plasma. Thrombin is a key enzyme in the coagulation process. It acts directly on fibrinogen to produce fibrin threads, which form the structural basis of a blood clot at the site of injury.
This test is important in identifying abnormalities in fibrinogen quantity or function and in detecting the presence of anticoagulants such as heparin or fibrin degradation products that may interfere with clot formation.
TCT is particularly useful in monitoring coagulation status in patients undergoing anticoagulant therapy or with suspected bleeding disorders. The test can be done alongside Prothrombin Time (PT), Activated Partial Thromboplastin Time (APTT), Fibrinogen Assay, and D-Dimer Test.
Patient Preparation
The patient should ideally not be on anticoagulation therapy at the time of testing, but should consult with the physician before the test.
Samples
1 ml of citrated blood collected in a Sodium citrate tube (blue top). Samples should be collected in a 3.2% buffered sodium citrate tube and mixed gently immediately after to ensure adequate mixing of the blood with the anticoagulant. The sample should be centrifuged for 10 minutes, and 2/3 of the plasma carefully separated and kept frozen until testing.
Reference Range
12-19 seconds
Results Turnaround
Within 24 hours after sample collection.
Diseases / Diagnostic indicators
The Thrombin Clotting Time test helps detect conditions that affect the final step of the coagulation cascade conversion of fibrinogen to fibrin.
Prolonged TCT may indicate:
- Hypofibrinogenemia or dysfibrinogenemia – low or abnormal fibrinogen levels
- Presence of heparin, especially in patients undergoing heparin therapy
- Fibrin degradation products – often elevated in disseminated intravascular coagulation (DIC)
- Liver disease – due to impaired synthesis of fibrinogen
Normal TCT usually rules out significant abnormalities in fibrinogen function or the presence of thrombin inhibitors.
This test is especially helpful in identifying the cause of abnormal clotting when other tests like PT or APTT are prolonged, or in monitoring anticoagulant therapy effectiveness.
For more on TT testing, read this study.