Partial Thromboplastin Time

Partial Thromboplastin Time (PTT)/Activated partial thromboplastin time (aPTT):
Laboratory test for the time to clot formation. Plasma is mixed with reagent. Measure of intrinsic coagulation pathway. Used to monitor oral anticoagulant therapy with heparin and identify bleeding disorders.
Increase  haemophilia, heparin, dissemination intravascular coagulation (DIC)
Decrease  hypercoaguable states

Mnemonic:
• PET – prothrombin time = extrinsic pathway factors
• PITT – partial thromboplastin time = intrinsic pathway factors