PTD - 47

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Test Directory -  Thrombin Time

Synonyms

TT

Clinical Indications

As part of an investigation of a bleeding or thrombotic episode, particularly to evaluate the level and function of fibrinogen; to detect heparin contamination. Also as part of the Thrombophilia screen

Request Form 

Combined Pathology Blood form (Yellow/Black or Blue for GP's)

Availability

On request after consulting with Haematology Consultant.

Specific Criteria

   

Turnaround Time

Thrombophilia screen: 21 days
If urgent: Same day

Specimen

Citrated Blood

Volume

9ml

Container

3 xBlue capped vacutainer tubes

Collection

 

Samples must be received by lab within 2 hours of collection.

Lab. Handling

Part of Thrombophilia screen: Citrated plasma double spun and frozen

Causes for Rejection

Inadequately labelled, unlabelled, haemolysed, under-filled, clotted or lipaemic samples.

Limitations

 

Sample activation, haemolysis, lipaemia.

Reference Range

 

Thrombin time: 16 -19 seconds

Interpretation

TT (Thrombin Time) > 19 suggestive of heparin contamination / reduction in functional fibrinogen.


Version 1.0 / January 2013