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Protein C, Activity

Test Code

1777

CPT Code(s)

85303

Preferred Specimen(s)

1 mL frozen platelet-poor plasma collected in 3.2% sodium citrate (light blue-top) tube

Minimum Volume

0.5 mL

Collection Instructions

Platelet-poor plasma: Centrifuge light blue-top tube for 15 minutes at approximately 1500 g within 60 minutes of collection. Using a plastic pipette, remove plasma, taking care to avoid the WBC/platelet buffy layer and place into a plastic vial. Centrifuge a second time and transfer platelet poor plasma into a new plastic vial. Plasma must be free of platelets (<10,000/mcl). Freeze immediately and ship on dry ice.

Specimen Container

Plastic screw-cap vial

Transport Temperature

Frozen

Specimen Stability

Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen -20° C: 14 days
Frozen -70° C: 1 year

Methodology

Clotting Assay

Performing Laboratory

Quest Diagnostics Nichols Institute
14225 Newbrook Drive
Chantilly, VA 20153

Setup Schedule

Set up: Tues-Sat (Evening shift); Report available: Next day

Limitations

Expected impact by therapeutic levels (potential interference depends upon drug concentration): Warfarin: decrease; Heparin (UFH or LMWH): UFH-no effect, LMWH-may falsely increase at higher levels; Dabigatran or Argatroban (Thrombin Inhibitors): may falsely increase; Rivaroxaban or Apixaban (Factor Xa Inhibitors): may falsely increase.

Reference Range(s)

70-180 % normal

Clinical Significance

The Protein C activity done by a RVV type matrix coagulation assay is more sensitive to subclinical vitamin K deficiency, hepatic failure, coumadin and DIC. Some genetic mutations of protein C will be missed by the chromogenic assay which will be satisfactorily detected with the protein C clottable assay system. Alternatively, chromogenic assay may be more reliable to measure half-life and recovery of protein C concentrates.

LOINC®' Code(s)

The Result and LOINC information listed below should not be used for electronic interface maintenance with Quest Diagnostics. Please contact the Quest Diagnostics Connectivity Help Desk for more information at 800-697-9302.

NOTE: The codes listed in the table below are not orderable Test Codes.

Result
Code
Result NameLOINC CodeComponent Name
2351AProtein C, Activity27819-2Protein C actual/Normal

Reference ranges are provided as general guidance only. To interpret test results use the reference range in the laboratory report.

The CPT codes provided are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.

LOINC assignment is based on a combination of test attributes, including the method used by the performing laboratory. For tests not performed by Quest Diagnostics, codes are assigned by the performing laboratory.

* The tests listed by specialist are a select group of tests offered. For a complete list of Quest Diagnostics tests, please refer to our Directory of Services.