aPTT

time

[tīm] a measure of duration. See under adjectives for specific times, such as bleeding time.activated partial thromboplastin time (APTT, aPTT) the period required for clot formation in recalcified plasma" >blood plasma after contact activation and the addition of platelet substitutes such as brain cephalins or similar phospholipids; used to assess the pathways" >coagulation pathways. A prolonged aPTT can indicate a deficiency of any of various coagulation factors, including factors XII, XI, IX, VIII, X, V, and II, and fibrinogen.AEC minimal response time the shortest duration at which x-ray exposure can be terminated by automatic exposure control.atrioventricular sequential time a fixed nonprogrammable interval that extends from the atrial stimulus to the ventricular stimulus.bleeding time the time required for a standardized wound to stop bleeding; used as a test for platelet disorders; see also bleeding time.circulation time the time required for blood to flow between two given points; see also circulation time.clotting time (coagulation time) the time required for blood to clot in a glass tube; see also clotting.cold ischemia time the time between the placement of a traumatically amputated body part in ice and the time of surgical replantation.inertia time the time required to overcome the inertia of a muscle after reception of a stimulus.ischemia time the total time between traumatic amputation of a limb or portion of a limb and its surgical reimplantation; it is the sum of warm and cold ischemia times.minimal response time in radiology, the shortest possible exposure time for an x-ray film to be exposed automatically.one-stage prothrombin time prothrombin time" >prothrombin time.prothrombin time see prothrombin time.real time a term used to describe a recording device that shows events simultaneously to their occurrence.R peak time intrinsicoid deflection.thrombin time the time required for plasma fibrinogen to form thrombin; see also thrombin time.warm ischemia time the time interval between traumatic amputation of a limb or part and its placement on ice.

aPTT

Abbreviation for activated partial thromboplastin time.

activated partial thromboplastin time

A test that evaluates the clotting factors of the intrinsic pathway—except VII and XIII—by measuring the time required to form a fibrin clot. aPTT is used to screen for bleeding tendencies and to monitor heparin therapy; it is increased in coagulation factor deficiencies (factors V, VIII, IX, X, XI, XII), DIC, Hodgkin lymphoma, hypofibrinogenemia, leukaemia, cirrhosis, vitamin K deficiency, von Willebrand’s disease, and in drug therapy—e.g., heparin and aspirin.

Ref range
30–40 seconds.

aPTT

Abbreviation for activated partial thromboplastin time.