- Transaction Code: 3230-03
- PT Code (Suggested): 85306
Protein S is a cofactor for Protein C-catalyzed inactivation of factors Va and VIIIa and its activity is determined by a similar assay. Heterozygous deficiency is associated with an increased risk of venous thrombosis, often occurring in the setting of acquired risk factors. As with Protein C, low Protein S levels can occur secondary to vitamin K deficiency, warfarin therapy, liver disease and disseminated intravascular coagulation (DIC). In addition, inflammatory conditions frequently give low or transiently depressed levels that may be distinguished by antigen level testing (below). Protein S has a relatively long half-life in circulation, comparable to factor X.
- Sample Required: 0.5 ml frozen plasma x4 or (2) 3.2% sodium citrated tubes, 5 ml each.
- See Sample Requirements when ordered with other tests.
- Normal Range: 70-140%
- Analytic Time: Within 5 working days
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