The<unk>  <unk> , also known as the activated<unk>  (aPTT or APTT), is a blood test that characterizes coagulation of the blood. A historical name for this measure is the kaolin-cephalin clotting time (KCCT), reflecting kaolin and cephalin as materials historically used in the test. Apart from detecting abnormalities in blood clotting,<unk>  is also used to monitor the treatment effect of heparin, a widely prescribed drug that reduces blood's tendency to clot. The<unk>  measures the overall speed at which blood clots form by means of two consecutive series of biochemical reactions known as the intrinsic pathway and common pathway of coagulation. The<unk>  measures the following coagulation factors: I (fibrinogen), II (prothrombin), V (proaccelerin), VIII (anti-hemophilic factor), X (Stuart–Prower factor), XI (plasma<unk>  antecedent), and XII (Hageman factor). The<unk>  is often used in conjunction with another measure of how quickly blood clotting takes place called the prothrombin time (PT). The PT measures the speed of clotting by means of the extrinsic pathway and common pathway.
Partial thromboplastin time
Activated clotting time
Thrombin time
Prothrombin time
Kaolin clotting time
Ecarin clotting time
Clotting time
Reptilase time