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Protein S Activity

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 plasma protein synthesized in the liver. Activated protein S acts as a cofactor to protein C, greatly potentiating its anticoagulant function.

STAT: < 24 hours (7 days a week)

Clot-based

Draw Tube: Blue Top

Sample Type: Citrated Plasma

Specimen Requirements

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

General Information

METHODOLOGY Clot-based
STAT TAT < 24 hours (7 days a week)
STAT TAT Performance > 90% of results released in 24 hours 7 days a week
ROUTINE TAT < 3 days (M-F)
ALTERNATIVE NAMES PS
DESCRIPTION The principle of the Protein S Activity assay is based upon the cofactor activity of protein S which enhances the anticoagulant action of activated protein C. This enhancement is reflected by the prolongation of the clotting time of a system enriched with factor Va which is a physiological substrate for activated protein C.
LIMITATIONS -
NORMAL RANGE 68-136%
ASSOCIATED TESTING -
REFERENCES -
SAMPLE REPORT Upon request
NEW YORK STATE APPROVED Yes

Test Codes

ORDER CODE P3100
CPT CODE 85306
LOINC CODE 27822-6