Protein S Activity

Test Code

PRS

CPT Codes
85303

Preferred Specimen

1 Blue

Minimum Volume

Blue top must be filled to Minimum Fill Indicator Line on tube.

Other Acceptable Specimens

none

Instructions

Outreach clients should double-spin the blue top plasma, remove the plasma from the RBC button, and freeze in a polypropylene tube.

Transport Container

BLUE, polypropylene tube

Transport Temperature

Blue - RT; polypropylene - frozen

Specimen Stability

Blue - 4 hours ambient; Plasma - 4 hours RT, 1 month frozen

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Sample must be free of clots and hemolysis.

Methodology
Colorimetric

Setup Schedule

Performed M, W & F (dayshift)

Report Available

Upon Completion of Analysis

Reference Range

54 - 137 %

Clinical Significance

Protein S is plasma vitamin K-dependent protein. Protein S is synthesized in the liver as an inactive precursor. The active form is obtained after carboxylation of glutamic residues by a vitamin K-dependent carboxylase. Protein S has an essential anticoagulant function. It acts as the cofactor of activated protein C, with which it appears to form a stoichiometric complex. This complex binds strongly to phospholipid surfaces and thus regulates the coagulation process, inhibiting thrombin-stimulated factors V and VIII. Protein S greatly enhances the anticoagulant function of activated protein C, probably by increasing protein C affinity for phospholipid membranes.

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.