antithrombin III

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Related to antithrombin III: antithrombin III test, protein C


any naturally occurring or therapeutically administered substance that neutralizes the action of thrombin and thus limits or restricts blood coagulation.
antithrombin I fibrin, referring to the capacity of fibrin to adsorb thrombin and thus neutralize it.
antithrombin III a naturally occurring inhibitor of blood coagulation; it is an α2-globulin member of the serpin group, synthesized in the liver and found in the plasma and various extravascular sites. It inactivates thrombin as well as certain coagulation factors and kallikrein. Inherited deficiency of the protein, an autosomal dominant disorder, is associated with recurrent deep vein thrombosis and pulmonary emboli. Complications from the disorder are prevented and, in conjunction with heparin, treated with a preparation of antithrombin III from pooled human plasma, administered intravenously.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

an·ti·throm·bin III

a plasma α2-globulin process that inhibits thrombin and has anticoagulant activities. Deficiency [MIM*107300] is commonly inherited as an autosomal dominant trait, caused by mutation in antithrombin III gene (AT3) or chromosome 1q; this is one of the few known mendelizing disorders from which thrombotic disease occurs.
Farlex Partner Medical Dictionary © Farlex 2012


A gene on chromosome 1q23-q25.1 that encodes antithrombin III, a member of the serine protease inhibitor (serpin) family that rapidly inhibits thrombin, as well as other activated serine proteases of the coagulation system, and regulates the coagulation cascade.

Molecular pathology
SERPINC1 mutations cause antithrombin-III deficiency.
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.

antithrombin III

Hematology A 58 kD α2-glycoprotein with a single polypeptide chain that inactivates serine proteases–thrombin and other coagulation proteins including factor Xa, IXa, kallikrein and others by an irreversible heparin-dependent reaction Function AT III dissolves blood clots that normally form within the circulation; heparin's anticoagulant activity hinges on activation of AT-III; AT-III-deficient individuals do not benefit from heparin therapy; ↓ AT-III may be a congenital AD condition, or acquired, occurring in DIC–due to 'consumption' or in liver disease–due to ↓ AT-III production, resulting in an ↑ risk of coagulation; AT III is ↓ in congenital deficiency, liver transplant, DIC, nephrotic syndrome, cirrhosis, chonic liver disease, carcinoma, mid-menstrual cycle; AT III is defective in 0.14% to 0.5% of the general population. See Hereditary thrombophilia, Recombinant human antithrombin III.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
One of the natural anticoagulant proteins, protein S activity in the children with bacterial pneumonia (68.6[+ or -]20.8%) was lower compared to the viral pneumonia patients (60.5[+ or -]17.7%, p=0.040), while there was no difference in terms of antithrombin III activity and protein C activity (Table II).
Kinjo et al., "Impact of Antithrombin III concentrates on portal vein thrombosis after splenectomy in patients with liver cirrhosis and Hypersplenism," Annals of Surgery, vol.
Table 2: Mean value of the Antithrombin III in stage 0 3 and 4 6.
Meanwhile, the tests ordered for differentitial diagnosis of thrombosis were as follows: Anti Factor X: 0.13 IU/mL (normal: 0.1-1.2), lupus anticoagulant: 53.5 s (normal: 20-60), Antithrombin III:68% (normal: 80-120), Protein S: 73% (normal: 60-140), Protein C: 18% (70-140), Homocystein: 19.41 umol/L (normal: 4.5-15).
The patient was advised to get her protein C, protein S and antithrombin III levels checked.
Pregnancy, due to its physiological changes such as increase in platelet adhesion, plasma viscosity, fibrinogen and coagulation factors, obstruction of venous return by gravid uterus, decreased levels of antithrombin III and decreased fibrinolysis, is a procoagulant state.
The pathogenesis involves acute transient decreases in proteins C and S, or antithrombin III levels.
The project in Charlton represents the first major expansion for rEVO since 2009 when it lauched sales of ATryn for patients with an inherited deficiency in the anti-clotting agent antithrombin III.
Methods of characterizing the individual phases of blood coagulation: prothrombin time; thrombin time; clotting fibrinogen; antithrombin III (AT III), protamine sulfate test, ethanol test.
A hypercoaguability work up revealed normal levels of factor V leiden, protein C, proteins S, antithrombin III, and homocystine.