ARUP's Laboratory Test Directory

Protein C, Total Antigen : 0030111

Mnemonic: PROT C

Ordering Recommendation: Not recommended for detecting protein C deficiency; preferred test is Protein C, Functional (0030113). Use to subtype deficiency in known protein C-deficient individuals. Do not order if individual has been on warfarin therapy in the previous 2-4 weeks.
Methodology: Enzyme Immunoassay
Performed: Sun-Sat
Reported: 1-2 days
Specimen Required: Collect: Lt. blue (sodium citrate). Refer to Specimen Handling at aruplab.com for hemostasis/thrombosis specimen handling guidelines.

Specimen Preparation: Transfer 2 mL platelet-poor plasma to an ARUP Standard Transport Tube. (Min: 1 mL)

Storage/Transport Temperature: CRITICAL FROZEN. Separate specimens must be submitted when multiple tests are ordered.

Unacceptable Conditions: Serum. Non-frozen or hemolyzed specimens.

Stability (collection to initiation of testing): Ambient: 4 hours; Refrigerated: Unacceptable; Frozen at -20°C: 3 months, at -70°C: 6 months
Reference Interval:
1-4 days: 17-53%
5-29 days: 20-64%
30-89 days: 21-65%
90-179 days: 28-80%
180-364 days: 37-81%
1-5 years: 40-92%
6-10 years: 45-93%
11 years and older: 63-153%
Interpretive Data: Patients on warfarin may have decreased protein C values. Patients should be off warfarin therapy for two weeks for accurate measurement of protein C.
CPT Code(s): 85302
Cross References: Protein C Antigen, Plasma (Protein C, Total Antigen), Protein C Immunologic (Protein C, Total Antigen)