thrombin time

time (tīm) a measure of duration. Symbol t.

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activated partial thromboplastin time  (APTT) (aPTT) (PTT) the period required for clot formation in recalcified blood plasma after contact activation and the addition of platelet substitutes; used to address the intrinsic and common pathways of coagulation.

bleeding time  the duration of bleeding after controlled, standardized puncture of the earlobe or forearm; a relatively inconsistent measure of capillary and platelet function.

circulation time  the time required for blood to flow between two given points.

clotting time , coagulation time the time required for blood to clot in a glass tube.

inertia time  the time required to overcome the inertia of a muscle after reception of a stimulus from a nerve.

one-stage prothrombin time  prothrombin t.

prothrombin time  (PT) the rate at which prothrombin is converted to thrombin in citrated blood with added calcium; used to assess the extrinsic coagulation system of the blood.

reaction time  the time elapsing between the application of a stimulus and the resulting reaction.

stimulus-response time  reaction t.

thrombin time  (TT) the time required for plasma fibrinogen to form thrombin, measured as the time for clot formation after exogenous thrombin is added to citrated plasma.

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thrombin

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.

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thrombin-thrombomodulin complex

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.

thrombin time

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.

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thrombin time

Thrombin 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.