Coagulation Studies

Thrombin Time

Normal range 14–19 seconds. Specimen: Plasma (sodium citrate).

Also known as: TT.

14–19 secondsReference range

Reference range

Conventionalseconds

1419

Specimen	Plasma (sodium citrate)
Conventional range	14–19 seconds
SI range	14–19 seconds
Conversion factor	×1 (conventional → SI)
Panel	Coagulation Studies

Convert any Thrombin Time result between units on the unit converter.

What is the normal range for Thrombin Time?

The standard teaching reference range for Thrombin Time is 14–19 seconds. This value is measured in plasma (sodium citrate).

Source: Adult reference values compiled from Pagana & Pagana, Mosby's Diagnostic and Laboratory Test Reference, and Fischbach & Dunning, A Manual of Laboratory and Diagnostic Tests. Reference ranges vary by laboratory, method, age, sex, and population — always use the range printed on the actual result.

Above the range

Common causes of a high Thrombin Time

Heparin
Low or abnormal fibrinogen
DIC
Direct thrombin inhibitors

At the bedside

Nursing considerations

Prolonged by heparin and by fibrinogen abnormalities.

Study aid

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Same panel

More Coagulation Studies tests

Activated Partial Thromboplastin Time (aPTT)25–35 seconds Bleeding Time2–7 minutes D-Dimer< 0.5 (negative) µg/mL FEU Fibrinogen200–400 mg/dL International Normalized Ratio (INR)0.8–1.1 (off anticoagulation) ratio Prothrombin Time (PT)11–13.5 seconds