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Protein S Antigen (Free)

Justification

Reduced protein S may be seen in warfarin therapy, pregnancy, use of oral contraceptives, DIC, acute thrombosis, HIV, nephrotic syndrome, liver disease and L-asparaginase chemotherapy. Congenital or acquired deficiency of protein S is also a risk factor for venous thromboembolism (VTE). Protein S is a vitamin K-dependent glycoprotein, and therefore it is reduced in patients stabilized on warfarin. Protein S is a cofactor for activated protein C, which inactivates procoagulant factors Va and VIIIa, thereby reducing thrombin generation. Protein S is also a cofactor for activated protein C in enhancing fibrinolysis. Free protein S measurement may be superior to functional protein S measurement in patients that have not been screened for the absence of the factor V Leiden (FVL) mutation.

STAT: < 1 week

ELISA

Draw Tube: Blue Top

Sample Type: Citrated Plasma

Specimen Requirements

Sample Type Volume Required Minimum Volume Stability
PREFERRED Citrated Plasma 1mL 0.5mL Room Temp.: 2 hours
Refrigerated: 2 hours
Frozen (-20C): 2 weeks
Frozen (-80C): 6 months
ALTERNATIVE - - - -
REJECTION CRITERIA Thawed in transit, refrozen or clotted sample
SPECIAL INSTRUCTIONS -

General Information

METHODOLOGY ELISA
STAT TAT < 1 week
STAT TAT Performance > 90% of results released in 1 week
ROUTINE TAT < 1 week
ALTERNATIVE NAMES PS Free
DESCRIPTION -
LIMITATIONS -
NORMAL RANGE -
ASSOCIATED TESTING -
REFERENCES -
SAMPLE REPORT Upon request
NEW YORK STATE APPROVED -

Test Codes

ORDER CODE P3101
CPT CODE 85306
LOINC CODE 27821-8