Helena Factor XII (10x1mL)

Factor XII (10x1mL)

Factor XII Deficient Substrate, 10 x 1 mL

Intended Use

The Factor XII Deficient Substrate Plasma is intended for the quantitative determination of Factor XII (Hageman Factor) in patients suspected of having a congenital or acquired deficiency of this coagulation protein.

Summary

Numerous coagulation factors have been identified in the blood, and are required for normal blood clotting. A deficiency of one or more of the factors may result in a notable hemorrhagic condition, the severity of which is governed by the degree of the deficiency. Deficiencies of the blood clotting factors may be congenital or acquired. The congenital deficiencies are, in general, single deficiency states while the acquired deficiencies may be multiple in nature, and commonly associated with liver disease, vitamin K deficiency or the ingestion of coumarin type anticoagulant drugs, and defibrination secondary to intravascular clotting.

Factor XII (Hageman Factor) is a unique coagulation protein. It is not essential for normal hemostasis, but it is essential for the normal clotting of blood in a test tube. Individuals with a deficiency in Factor XII do not suffer from hemorrhagic conditions, but they have a profoundly abnormal clotting time. The condition is usually discovered because routine testing (i.e. surgical work-up) reveals an abnormal clotting time.

In an effort to devise a quantitative assay for Factor XII, several methods based on the thromboplastin test were used and were found to be time consuming and complicated. Langdell, Wagner and Brinkhous (1953) developed a one-stage “partial thromboplastin time” which was simple to perform but not reproducible. Helena’s procedure determines Factor XII activity by using a modification of the activated partial thromboplastin time (APTT) test and a Factor XII deficient substrate plasma.