PTD - 53

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Test Directory -  Prothrombin Time 50/50 Correction



Clinical Indications

Follow up test to investigate cause of unexplained prolonged PT. Differentiates between possibility of factor deficiency or acquired coagulation inhibitors of the extrinsic and common pathways.

Request Form 

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


On Request after consultation with Consultant Haematologist

Specific Criteria


DO NOT use heparinised syringes / lines for collecting coagulation screens. Patient should be bled with minimal stasis, and samples received in lab within 2 hours of collection.

Turnaround Time

2 weeks or same day if required urgently


 Citrated whole blood




  1 x Blue capped vacutainer tubes


  Samples must be received by lab within 2 hours of collection. Avoid prolonged stasis during venepuncture

Lab. Handling

Samples must be received within 2 hours of collection. If not processed immediately they need to be double spun, plasma aliquoted and frozen.

Causes for Rejection

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


  Activated sample, sample haemolysis or lipaemia..

Reference Range

  ICorrection of prolonged PT : Suggestive of Factor deficiency                    No correction of PT (to within 3 - 4 seconds): Suggestive of inhibitor


See patient test report

Version 1.0 / January 2013