PTD - 12

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Test Directory -  Prothrombin Time & INR

Synonyms

PT

Clinical Indications

Prothrombin time (PT) and International Normalised Ratio (INR) ordered as part of coagulation screen or separately to help diagnose unexplained bleeding or for monitoring of oral anticoagulant therapy.

Test Includes

.PT & INR

Request Form 

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

Oral anticoagulant dosing form.

Availability

On Request

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

Within 2 hours of reaching the lab

Specimen

 Citrated whole blood

Volume

 3ml

Container

  1 x Blue capped vacutainer tubes

Collection

  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.

Causes for Rejection

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

Limitations

  Activated sample, sample haemolysis or lipaemia..

Reference Range

  INR (No anticoagulants): 0.8 to 1.2
Oral anticoagulation INR:
Low - 2.0 - 3.0
Intermediate - 2.5 - 3.5
High - 3.5  - 4.5

Interpretation

See patient test report

Version 1.0 / January 2013