| PTT | <haematology, investigation> A test used to evaluate the blood clotting. If there is a deficiency in a particular blood clotting factor, the time required for clotting will be lengthened. Patients with severe liver disease, Von Willebrand disease or haemophilia will have an abnormal (prolonged) PTT test. Heparin, a medication given to thin the blood, will prolong the PTT, making this a useful test for regulating heparin dosing. (15 Dec 1997) |
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