| factor vii assay | A test used to measure the activity of a blood clotting factor VII. This test may be used to evaluate excessive bleeding. Abnormally low factor VII assays may be seen in the following conditions: congenital deficiency of factor VII, fat malabsorption, heparin administration, cirrhosis, vitamin K deficiency and warfarin administration. (27 Sep 1997) |
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| factor vii deficiency | An inherited disorder that causes abnormal blood clotting due to the congenital absence of one of the 20 different plasma proteins involved in the coagulation process. Symptoms include bleeding of the gums, nosebleeds, easy bruising, bleeding in muscles or joints and excessive menstrual bleeding. Treatment includes the administration of plasma concentrates of factor VII (extrinsic factor). (27 Sep 1997) |
| factor viii | A coagulation (clotting) factor. Classic haemophilia (haemophilia A) is due to a congenital deficiency in the amount (or activity) of factor VIII. Factor VIII is also known as antihemophiliac factor (AHF) or antihemophiliac globulin (AHG). The gene for factor VIII (that for classic haemophilia) is on the X chromosome so females can be silent carriers without symptoms and males can be haemophiliacs. (12 Dec 1998) |
| factor viiia | <chemical> Activated form of factor viii. The b-domain of factor viii is proteolytically cleaved by thrombin to form factor viiia. Factor viiia exists as a non-covalent dimer in a metal-linked (probably calcium) complex and functions as a cofactor in the enzymatic activation of factor x by factor ixa. Factor viiia is similiar in structure and generation to factor va. Chemical name: Blood-coagulation factor VIIIa, procoagulant (12 Dec 1998) |
| factor viii assay | A test used to measure the activity of a blood clotting factor VIII (Von Willebrand factor). This test is usually used to monitor treatment of haemophilia. Abnormally low factor VIII assays may be seen in the following conditions: congenital deficiency of factor VIII (haemophilia), DIC and secondary fibrinolysis. This test may also be performed in the evaluation of Von Willebrand's disease. (27 Sep 1997) |
| factor viii deficiency | A sex-linked genetic disease affecting males that results from a deficiency of clotting factor VIII, a protein factor that is required for normal blood coagulation. Symptoms include easy bruising, bleeding gums, nosebleeds and bleeding into muscle tissue (haematoma) or a joint space (haemarthrosis). Treatment includes the infusion of factor VIII concentrate intravenously to restore this essential factor and normalize blood coagulation. Inheritance: sex-linked. (27 Sep 1997) |
| factor x | <chemical> Storage-stable glycoprotein blood coagulation factor that can be activated to factor xa by both the intrinsic and extrinsic pathways. A deficiency of factor x, sometimes called stuart-prower factor deficiency, may lead to a systemic coagulation disorder. Chemical name: Blood-coagulation factor X (12 Dec 1998) |
| factor xa | <enzyme> Activated form of factor x that participates in both the intrinsic and extrinsic pathways of blood coagulation. It catalyses the conversion of prothrombin to thrombin in conjunction with other cofactors. Registry number: EC 3.4.21.6 (12 Dec 1998) |
| factor x assay | A test used to measure the activity of a blood clotting factor X. This test may be used to evaluate excessive bleeding. Abnormally low factor X assays may be seen in the following conditions: congenital deficiency of factor X, fat malabsorption, heparin administration, cirrhosis, vitamin K deficiency and warfarin administration. (27 Sep 1997) |
| factor x deficiency | Blood coagulation disorder usually inherited as an autosomal recessive trait, though it can be acquired. It is characterised by defective activity in both the intrinsic and extrinsic pathways, impaired thromboplastin time, and impaired prothrombin consumption. (12 Dec 1998) |
| factor X for Haemophilus | <physiology> A substance, in the form of reddish brown, microscopic, prismatic crystals, formed from dried blood by the action of strong acetic acid and common salt; called also Teichmann's crystals. Chemically, it is a hydrochloride of haematin. The obtaining of these small crystals, from old blood clots or suspected blood stains, constitutes one of the best evidences of the presence of blood. Origin: Gr. Blood. Source: Websters Dictionary (01 Mar 1998) |
| factor xi | <chemical> Stable blood coagulation factor involved in the intrinsic pathway. The activated form xia activates factor ix to ixa. Deficiency of factor xi is often called haemophilia c. Chemical name: Blood-coagulation factor XI (12 Dec 1998) |
| factor xia | <enzyme> Activated form of factor xi. In the intrinsic pathway, factor xi is activated to xia by factor xiia in the presence of cofactor hmwk (high molecular weight kininogen). Factor xia then activates factor ix to factor ixa in the presence of calcium. Registry number: EC 3.4.21.27 (12 Dec 1998) |
| factor xi deficiency | A deficiency of blood coagulation factor xi (known as plasma thromboplastin antecedent or pta or antihemophilic factor c) resulting in a systemic blood-clotting defect called haemophilia c or rosenthal's syndrome, that may resemble classical haemophilia. (12 Dec 1998) |
| factor xii | <chemical> Stable blood coagulation factor activated by contact with the subendothelial surface of an injured vessel. Along with prekallikrein, it serves as the contact factor that initiates the intrinsic pathway of blood coagulation. Kallikrein activates factor xii to xiia. Deficiency of factor xii, also called the hageman trait, leads to increased incidence of thromboembolic disease. Chemical name: Blood-coagulation factor XII (12 Dec 1998) |