Protein C (Functional)

Test Code

PRC

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 - 8 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

65 - 134 %

Clinical Significance

Like the coagulation factors, Protein C is present in the plasma as a pro-enzyme. Its transformation into an active enzyme requires the presence of thrombin, calcium and phospholipids. This thrombin-dependent activation of protein C is potentiated by an endothelial factor, thrombomodulin. In the activated state, protein C regulates the coagulation process by neutralizing the procoagulant activities of the factors Va and VIIIa in the presence of cofactor Protein S. This limits thrombus extension and acts as a major regulator of the coagulation process. Protein C belongs to the Vitamin K-dependent proteins and is synthesized in the liver. Production of a functional protein C molecule depends on the carboxylation of the glutamic residues of a precursor molecule by a hepatic carboxylase. The cofactor of the hepatic carboxylase is Vitamin K. In case of a Vitamin K deficiency, this carboxylation is reduced, and the inactive precursor appears in circulation.

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.