Protein C, Functional with Reflex to Protein C, Total Antigen
Also known as: PROT CF R
Use
The Protein C, Functional with Reflex to Protein C, Total Antigen test is used to detect and subtype protein C deficiency, which may be a risk factor for thrombosis when acquired conditions are not present. It measures protein C activity and antigen levels to aid in the diagnosis of inherited or acquired conditions that reduce protein C activity, such as vitamin K deficiency, anticoagulant therapy, liver disease, or disseminated intravascular coagulation (DIC). Detecting and managing these conditions are crucial for preventing thromboembolic events.
Special Instructions
This test requires careful patient preparation: patients should discontinue warfarin therapy at least two weeks prior to testing to ensure accurate measurement of protein C levels. It is important to follow specimen handling guidelines for hemostasis and thrombosis tests. If Protein C Functional levels are decreased, the Protein C, Total Antigen test will be reflexively added, resulting in additional charges.
Limitations
The measurement of protein C may be artificially decreased in specimens with elevated factor VIII levels, and overestimated in the presence of anticoagulants such as heparin, direct thrombin inhibitors, or direct factor Xa inhibitors. Repeat testing might be necessary to confirm low values after excluding these acquired conditions. Differential diagnoses should consider other causes of protein C deficiency before concluding an inherited deficiency. Protein C values can also be impacted by vitamin K levels, warfarin therapy, liver disease, acute thrombosis, and asparaginase therapy.
New York Approved
Methodology
Immunoassay (ELISA)
Biomarkers
LOINC Codes
- 27819-2
Result Turnaround Time
1-5 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
2 mL
Minimum Volume
1 mL
Container
Lt. blue (sodium citrate)
Collection Instructions
Refer to Specimen Handling guidelines at aruplab.com for details on hemostasis and thrombosis specimen handling.
Patient Preparation
Patients should not be on warfarin therapy for at least two weeks prior to specimen collection.
Storage Instructions
Transport frozen. Specimens must remain frozen during transport.
Causes for Rejection
Serum. EDTA plasma, clotted, or hemolyzed specimens.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 4 hours |
| Refrigerated | Unacceptable |
| Frozen | 3 months |