Protein C Antigen
Use
Confirmation and characterization of protein C deficiency
Special Instructions
If the patient's hematocrit exceeds 55%, the volume of citrate in the collection tube must be adjusted. Refer to Coagulation Collection Procedures for directions.
Limitations
Individuals with heterozygous PC deficiency may have low normal PC levels. Treatment with warfarin decreases the levels of vitamin K-dependent factors including PC. PC levels drop after six hours of warfarin treatment and generally regain pretreatment levels two weeks after cessation of therapy. PC levels can be depleted as the result of activation of coagulation, limiting the utility of testing for congenital PC deficiency during the immediate convalescent period after a thrombotic event.
Methodology
Immunoassay (Other)
Biomarkers
LOINC Codes
- 27820-0
- 27820-0
Result Turnaround Time
2-4 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
1 mL
Minimum Volume
Not provided
Container
Blue-top (sodium citrate) tube
Collection Instructions
Blood should be collected in a blue-top tube containing 3.2% buffered sodium citrate. Evacuated collection tubes must be filled to completion to ensure a proper blood-to-anticoagulant ratio. Mix immediately by gentle inversion to ensure adequate mixing. A discard tube is not required except when using a butterfly collection system. In that case, draw a discard tube first. Collect noncitrate tubes (e.g., sterile/red-top) prior to citrate tubes.
Patient Preparation
Avoid warfarin (Coumadin®) therapy for two weeks and heparin therapy for two days prior to the test. Do not draw from an arm with a heparin lock or heparinized catheter.
Storage Instructions
Freeze.
Causes for Rejection
Gross hemolysis; clotted specimen; frozen specimen thawed in transit; improper labeling
Stability Requirements
| Temperature | Period |
|---|---|
| Frozen | 28 days |