Specimen Requirements
Title
Protein C, Functional
Specimen Requirement
Collect a light blue sodium citrate, immediately invert six times, send whole blood room temperature same day as collected.
Patient Preparation:
Ideally, the patient should not be on anticoagulant therapy. Avoid warfarin (Coumadin®) therapy for two weeks prior to the test and heparin, direct Xa, and thrombin inhibitor therapies for about three days prior to testing. Do not draw from an arm with a heparin lock or heparinized catheter.
Methodology
Protein C in plasma is activated by a specific enzyme (protein C activator) from copperhead snake venom (Agkistrodon contortrix). The amount of activated protein C is determined. The resulting activated PC (Protein Ca) is determined as the rate of hydrolysis of a chromogenic substrate in a kinetic test by measuring the increase in absorbance at 405 nm.
Stability
Room temp: 24 hours, Refrigerated: Unacceptable, Frozen: 28 days
Reference Range
The reference range is determined by the performing laboratory and will show on the report.
Turnaround
2-3 days
Clinical Use
Confirmation and characterization of protein C deficiency
Test Code
PTCAS