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When should I return my sample over the bank holiday? Find out more.



Prothrombin is a plasma protein produced by the liver. A prothrombin time test measures how long it takes for the blood to clot. Clotting is caused by a series of clotting factors activating each other, including the conversion of prothrombin to thrombin.

What might a high result mean?

An increased prothrombin time indicates your blood is taking longer to form a clot. If you are not taking anticoagulant drugs and your prothrombin time is prolonged, additional testing may be necessary to determine the cause.