Laboratory Medicine
Test Directory / Thrombin Time (TT)
Thrombin Time (TT)
Citrate Plasma
| Test | Thrombin Time (TT) |
|---|---|
| Common Abbreviations | TT, TCT |
| Profile | If required as part of a Thrombophilia Screen Antithrombin (AT), Protein C (PC), Protein S (PS) Thrombin Time (TT), Factor V Leiden (FVL), Prothrombin Gene Mutation (F2G), Lupus Inhibitor (LIS), Anticardiolipin (ACA), Coagulation Screen (CLS) |
| Clinical Indication | The thrombin time measures the conversion of fibrinogen to fibrin after the addition of thrombin to plasma. Thrombin enzymatically cleaves fibrinopeptides A and B from the alpha and beta chains of fibrinogen, allowing for polymerization in fibrin. The thrombin time test will be prolonged in Disseminated Intravascular Coagulation (DIC), thrombin inhibitors (heparin, Dabigatran), in the presence of low levels (typically < 0.7-1 g/L) of fibrinogen and in structurally abnormal fibrinogen (dysfibrinogenaemia). Additionally, elevated levels of fibrinogen, fibrin degradation products (FDP) or the presence of paraproteins may prolong the thrombin time. |
| Specimen Type | Blood |
| Sample Type | Citrated Plasma (& Brown clotted serum, gel barrier if part of a thrombophilia screen) |
| Minimum Volume | 1 x 3 mL (adult) |
| Special Precautions | |
| Stability | 4 - 6 hrs |
| Turnaround Time | Urgent: York 2hrs/Scarborough 4hrs - call lab prior. Routine: 4-6 weeks |
| Laboratory | York Hospital |
| Reference Interval | Issued with final report |
| Limitations | A normal thrombin time excludes the presence of a clinically significant Dabigatran level. |
| Additional Information |
