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Test Code CFX Protein C Activity, Plasma

Reporting Name

Protein C Activity, P

Useful For

As an initial test for evaluating patients suspected of having congenital protein C deficiency, including those with personal or family histories of thrombotic events

 

Detecting and confirming congenital type I and type II protein C deficiencies

 

Detecting and confirming congenital homozygous protein C deficiency

 

Identifying decreased functional protein C of acquired origin (eg, due to oral anticoagulant effect, vitamin K deficiency, liver disease, intravascular coagulation and fibrinolysis/disseminated intravascular coagulation)

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Plasma Na Cit


Ordering Guidance


Coagulation testing is highly complex, often requiring the performance of multiple assays and correlation with clinical information. For that reason, consider ordering AATHR / Thrombophilia Profile, Plasma and Whole Blood.



Necessary Information


1. If the patient is being treated with Coumadin, this should be noted. Coumadin will lower protein C.

2. Heparin (unfractionated or low molecular weight) 2 U/mL or more may interfere with this assay.



Specimen Required


Specimen Type: Platelet-poor plasma

Patient Preparation: Fasting

Collection Container/Tube: Light-blue top (3.2% sodium citrate)

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Collection Instructions:

1. For complete instructions, see Coagulation Guidelines for Specimen Handling and Processing.

2. Centrifuge, transfer all plasma into a plastic vial, and centrifuge plasma again.

3. Aliquot plasma into a plastic vial leaving 0.25 mL in the bottom of centrifuged vial.

4. Freeze plasma immediately (no longer than 4 hours after collection) at -20° C or, ideally, at -40° C or below.

Additional Information:

1. Double-centrifuged specimen is critical for accurate results as platelet contamination may cause spurious results.

2. Each coagulation assay requested should have its own vial.


Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Plasma Na Cit Frozen 14 days

Day(s) Performed

Monday through Friday

Test Classification

This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

85303

LOINC Code Information

Test ID Test Order Name Order LOINC Value
CFX Protein C Activity, P 27818-4

 

Result ID Test Result Name Result LOINC Value
CFX Protein C Activity, P 27818-4

Report Available

1 to 3 days

Reject Due To

Gross hemolysis Reject
Gross lipemia Reject
Gross icterus Reject

Method Name

Chromogenic

Reference Values

70-150%