Protein C Antigen, Plasma
Use
This test is useful for differentiating congenital type I protein C deficiency from type II deficiency. It helps in evaluating the significance of decreased functional protein C, especially when decreased protein C activity might be congenital rather than acquired, such as due to oral anticoagulant effect, vitamin K deficiency, liver disease, or intravascular coagulation and fibrinolysis/disseminated intravascular coagulation. It is not useful for predicting a thrombotic event.
Special Instructions
If the patient is being treated with Coumadin (warfarin), it should be noted as it will lower protein C. Each coagulation assay requested should have its own vial. Consider ordering additional tests like Thrombophilia Profile, Plasma and Whole Blood for comprehensive assessment.
Limitations
The test has not been cleared or approved by the US Food and Drug Administration. Platelet contamination may cause spurious results, thus a double-centrifuged specimen is critical for accurate results. Acquired protein C deficiency is of uncertain clinical hemostatic significance, and the clinical significance of increased protein C levels is unknown.
New York Approved
Methodology
Immunoassay (ELISA)
Biomarkers
LOINC Codes
- 27820-0
- 27820-0
Result Turnaround Time
3-7 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
1 mL
Minimum Volume
0.5 mL
Container
Light-blue top (3.2% sodium citrate); Submission: Polypropylene plastic vial
Collection Instructions
For complete instructions, see Coagulation Guidelines for Specimen Handling and Processing. Centrifuge, transfer all plasma into a plastic vial, and centrifuge plasma again. Aliquot plasma into a plastic vial leaving 0.25 mL in the bottom of centrifuged vial. Freeze plasma immediately (no longer than 4 hours after collection) at -20 degrees C or ideally, at -40 degrees C or below.
Patient Preparation
Fasting: 8 hours, preferred but not required
Causes for Rejection
Gross hemolysis, gross lipemia
Stability Requirements
| Temperature | Period |
|---|---|
| Frozen | 2 years |