Protein S is a vitamin K dependent protein. It is a physiological inhibitor of coagulation. It acts as a cofactor of activated protein C by promoting the inactivation of FVa and FVIIIa, prothrombin, of the prothrombinase complex, FX.
A protein S deficiency can be either acquired (hepatocellular insufficiency, vitamin K deficiency, anti-protein S antibody, ...) or constitutional (heterozygous or homozygous deficiency) grouped into 2 types depending on whether the deficiency is quantitative (type I) or qualitative (type II).
Dilutions of normal plasmas are carried out in a plasma deficient in Protein S.
The plasmas diluted are then activated by a reagent containing factor Xa, activated Protein C and phospholipids. After 5 minutes of incubation, the clot formation is triggered by the addition of calcium chloride.
Under these conditions, the prolongation of the clotting time is directly proportional to the concentration of Protein S present in the plasma.
The kit allows the performance of 40-160 tests, depending on the performance of the assay by manual or automatic method and depending on the type of instrument used.
The lyophilized presentation allows greater stability until the expiration date.
Activation reagent (R1):
- 4 vials x 1 mL, lyophilized.
Each vial contains Human Activated Protein C, Bovine Factor Xa and Phospholipids.
Protein S (R2) deficient plasma:
- 4 vials x 1 mL, freeze-dried
Sample dilution buffer 10 x concentrate (R3)
Plasma control Protein S (R4):
- 2 vials x 0.5 mL, freeze-dried