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1. the activated form of coagulation factor II (prothrombin), which catalyzes the conversion of fibrinogen to fibrin.
2. a preparation of this compound prepared from prothrombin of bovine origin, used as a topical hemostatic.
thrombin time (TT) the time required for plasma fibrinogen to form thrombin: exogenous thrombin is added to citrated plasma and the time to clot formation is measured. Prolonged TT is seen with abnormalities of fibrinogen and in the presence of heparin or degradation products of fibrin or fibrinogen.
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 blood plasma after contact activation and the addition of platelet substitutes such as brain cephalins or similar phospholipids; used to assess the 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 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.
the time needed for a fibrin clot to form after the addition of thrombin to citrated plasma; prolonged thrombin time is seen in patients receiving heparin therapy.
thrombin timeThrombin clotting time Lab medicine A test used to evaluate the final stage of coagulation–the conversion of fibrinogen to fibrin; it is ↑ in deficiency or defects of fibrinogen, or in the presence of FDPs or heparin-coagulation products; it is used clinically to determine adequacy of thrombolytic therapy. See Reperfusion therapy, Streptokinase, tPA, Urokinase.
throm·bin time(TT) (thrombin tīm)
Duration needed for a fibrin clot to form after the addition of thrombin to citrated plasma; thrombase.
an enzyme resulting from activation of prothrombin, which catalyzes the conversion of fibrinogen to fibrin. It is also a potent stimulus to the aggregation of platelets. A preparation from prothrombin of bovine origin is used as a topical hemostatic.
thrombomodulin, a specific endothelial cell surface receptor, converts thrombin, a very weak activator of protein C in the anticoagulant pathway, to the status of a very active protein C activator.
the time required for a standardized solution of thrombin to clot plasma. It is a measure of the rate of conversion of fibrinogen to fibrin.