At a Glance
Why Get Tested?
To check how well clot-preventing medications (anti-coagulants) are working to prevent blood clots, to investiate the clotting tendency of blood, liver damage and vitamin K status
When to Get Tested?
If you are taking an warfarin-related anti-coagulant drug or think you may have a bleeding disorder
A blood sample drawn from a vein in the arm. Your doctor will advise you on how frequent this testing will be.
Test Preparation Needed?
The Test Sample
What is being tested?
The test measures how long it takes for your blood to begin to form clots. Prothrombin is a plasma protein produced by the liver. Clotting is caused by a series of chemical reactions (coagulation cascade), including the conversion of prothrombin to thrombin. The test used to measure this clotting factor is called prothrombin time, INR or PT.
How is the sample collected for testing?
Blood is collected by needle from a vein in the arm.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed.
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