Thromboplastin

thromboplastin /throm·bo·plas·tin/ (-plas´tin) coagulation factor III.

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tissue thromboplastin  coagulation factor III.

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throm·bo·plas·tin (thrmb-plstk)

n.

A plasma protein present in tissues, platelets, and white blood cells necessary for the coagulation of blood and, in the presence of calcium ions, necessary for the conversion of prothrombin to thrombin. Also called factor III, platelet tissue factor, thrombokinase.

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Thromboplastin

A protein in blood that converts prothrombin to thrombin.

Mentioned in: Prothrombin Time

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thromboplastin (throm´bōplas´tin),

n a substance necessary to the coagulant activity of tissue extracts; also has been referred to as the direct activator of prothrombin and as a substance from plasma, platelets, and tissues that initiates thromboplastic activity in blood coagulation. See also thromboplastin, extrinsic.

thromboplastin, activated,

n See thromboplastin, extrinsic.

thromboplastin, cofactor of,

n See factor V.

thromboplastin, extrinsic,

n a direct prothrombin activator formed by the interaction of brain extracts, factors V and VII, and factor IV calcium (Ca⁺⁺).

thromboplastin, incomplete,

n tissue thromboplastin.

thromboplastin, intrinsic (plasma thromboplastin, intrinsic prothrombin activator),

n a prothrombin activator formed from interaction of blood coagulation factors V, VIII, IX, and X and factor IV calcium (Ca⁺⁺) with a foreign surface.

thromboplastin, partial time (PTT),

n a blood test used to determine von Willebrand disease, hemophilia, and to monitor anticoagulant medications. Normal coagulation time is 68 to 82 seconds. An updated form of the test, activated partial thromboplastin time (APTT), is replacing PTT.

thromboplastin, tissue,

n a factor in tissue extract responsible for coagulation of blood.

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thromboplastin

a substance in blood and tissues which, in the presence of ionized calcium, aids in the conversion of prothrombin to thrombin. Extrinsic and intrinsic thromboplastin are formed as the result of the interaction of different clotting factors; the factors that combine to form extrinsic thromboplastin are not all derived from intravascular sources, whereas those that form intrinsic thromboplastin are.

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activated partial thromboplastin time

see activated partial thromboplastin time.

extrinsic thromboplastin

the prothrombin activator formed as a result of interaction of coagulation factors III, VII, and X which, with factor IV, aids in the formation of thrombin.

thromboplastin generation time (TGT)

evaluates the first stage in blood coagulation by measuring the efficiency of prothrombinase formation.

intrinsic thromboplastin

the prothrombin activator formed as a result of interaction of coagulation factors V, VII, IX, X, XI and XII and platelet factor 3 (PF-3), which, with factor IV, aids in the conversion of prothrombin to thrombin.

plasma thromboplastin antecedent (PTA)

clotting factor XI; deficiency occurs in cattle and dogs, causing mild to severe bleeding tendencies called hemophilia C.

plasma thromboplastin component (PTC)

clotting factor IX; deficiency causes christmas disease. Called also Christmas factor, antihemophilic factor B, autoprothrombin II.

thromboplastin time

see activated partial thromboplastin time.

tissue thromboplastin

factor III, a material derived from several sources in the body (e.g. brain, lung), and is important in the formation of extrinsic prothrombin converting principle in the extrinsic pathway of blood coagulation. Called also tissue factor.