PTT definition

<acronym>

Preferred term: Post, Telephone and Telegraph administration

<acronym>

<investigation>

<haematology> 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)