The partial thromboplastin time (PTT) or activated partial thromboplastin time (APPT) is a blood test that characterises coagulation of the blood. A historical name for this measure is the kaolin-cephalin clotting time, reflecting kaolin and cephalin as materials historically used in the test.

SPECIMEN: 3 mL whole blood in 1 Blue Top (Sodium Citrate) tube. Mix thoroughly by inversion. Transport to Lab within 4 hours. If this is not possible, make PPP within 1 hour of collection as follows: Centrifuge sample at 3600 rpm for 15 min. & transfer supernatant to a clean plastic tube. Centrifuge this supernatant again at 3600 rpm for 15 min. & finally transfer the supernatant (PPP) to 1 labelled clean plastic screw capped vial. FREEZE IMMEDIATELY. Ship frozen. DO NOT THAW.
STABILITY: Room: 4 hrs; Refrigerated: 4 hrs; Frozen: 2 weeks
REPORT: Daily
USAGE: PPT or APTT measures intrinsic and common pathways of the coagulation cascade. Prolonged APTT may be caused by heparin and other anticoagulants, factor deficiencies or inhibitors such as lupus anticoagulants.