Factor VII Quick Facts
- Synonym: Proconvertin
- Molecular mass: 50 000 D
- Synthesis: Liver
- Half-life: 2 – 5 hours
- Plasma concentration: 470μg/l or 9,4nmol/l
- Normal range: 70 – 120% or 0.7 – 1.2U/ml
Biochemistry of Factor VII
The activation of the extrinsic coagulation system is initiated by the exposure of tissue thromboplastin (tissue factor) from damaged tissue, which leads to the activation of factor VII to factor VIIa. factor X subsequently is activated to factor Xa by the complex of tissue thromboplastin and factor VIIa. factor Xa activates factor VII in a positive feedback mechanism. Recent studies have shown, that factor VIIa can also activate factor IX of the intrinsic coagulation system. Synthesis of factor VII is vitamin K-dependent. Clinical significance of Factor VII Inherited FVII deficiency is rare. Acquired FVII deficiency can be due to vitamin K-deficiency, hepatic disease, massive blood loss or DIC. FVII deficiency is associated with a bleeding tendency. Increased factor VII values as can be observed, depending on age and weight, during the use of oral contraceptives, in the post-menopausal phase, during pregnancy, postoperatively and in phase I of DIC are regarded as risk factors for cardiovascular and cerebrovascular diseases. A correlation between acute thrombosis and increased factor VII concentrations is also subject of discussion.
Clinical or Research use of Factor VII
- Diagnosis of a to date unknown, hereditary bleeding disorder
- Determination of the concentration during anticoagulant therapy with heparin or coumarin derivatives (during the transition phase)
- Potential risk indicator for coronary heart disease