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Also known as: Prothrombin Time; PT
Formal name: Prothrombin Time

At a Glance

Why Get Tested?

To help diagnose a bleeding disorder; to help estimate the severity of liver disease. A tightly controlled version of the PT called the International Normalised Ratio (INR) is used to measure the effect of anticoagulant drugs such as warfarin.

When to Get Tested?

No test preparation is needed. If the patient is receiving anticoagulant therapy, the specimen should be collected before the daily dose is taken. It is essential the blood is taken quickly and smoothly and that the anticoagulant bottle is filled exactly to the designated mark or the result may be inaccurate.

Sample Required?

A blood sample taken from a vein in the arm

Test Preparation Needed?

None needed, although if you are receiving anticoagulant therapy, the sample should be collected before taking your daily dose.