Laboratory Test Guide

Protein C Activity

General Information

Lab Name

Protein C Activity

Lab Code

PCCLOT

Epic Name

Protein C Activity

Description

Protein C Activity is a quantitative assay to determine the functional protein C levels in plasma using synthetic chromogenic substrate. Acquired or congenital protein C deficiency is associated with increased risk for venous thrombosis. This assay is not affected by heparin, direct thrombin inhibitors or direct Xa inhibitors. Warfarin or other vitamin K antagonists (VKA) reduce protein C levels and patients should wait at least 2 weeks after the last dose of VKA to measure protein C levels.

This is the preferred initial test to evaluate for congenital protein C deficiency.

**Laboratory Medicine resident approval is required for hospital inpatients and patients in the Emergency Department.**

Synonyms

Protein C Chromogenic, Protein C Functional, Protein C Level

Interpretation

Method

Stago STA Stachrom Protein C

Reference Range

Units: %

Female		Male
Age	Range	Age	Range
0-29d	20-150	0-29d	20-150
1m-2m	21-150	1m-2m	21-150
3m-5m	28-150	3m-5m	28-150
6m-11m	37-150	6m-11m	37-150
1y-5y	40-150	1y-5y	40-150
6y-9y	45-150	6y-9y	45-150
10y-	65-150	10y-	65-150

Effective date: 07/01/2004

Ref. Range Notes

Elevated Protein C is not associated with thrombosis or bleeding.

Interferences and Limitations

This assay is insensitive to hemoglobin (up to 2 g/l), bilirubin (up to 200 mg/l) and triglycerides (up to 4 g/l). PIVKA protein C (PIVKA: protein induced by vitamin K antagonists) present in the plasma of patients receiving oral anticoagulant therapy may be measured by the colorimetric method.

Patients on warfarin therapy may see decrease in protein C activity because of the vitamin K antagonistic effect of the drug. Protein C is a vitamin K dependent factor.

The presence of aprotinin in the plasma may result in an underestimation of the protein C level.

Ordering & Collection

Specimen Type

Blood

Collection

3 or 5 mL BLUE TOP (CITRATE) tube

Forms & Requisitions

Outside clients should fill and submit Coagulation Patient Clinical History Form: Coagulation Patient Clinical History Form

Approval Required

Laboratory Medicine resident's approval is required for hospital inpatients and patients in Emergency Department.

Handling Instructions

The Laboratory MUST process specimen, within 4 hrs of blood collection.

Quantity

requested: entire specimen

Processing

**Laboratory Medicine resident's approval is required for hospital inpatients and patients in Emergency Department.** Approval is NOT required for hospital outpatients, clinic patients or outside clients.

UW-MT Instructions: Take specimen to UW-MT Coag lab for processing. Coag tech will freeze plasma sample for transport to HMC Coag."

HMC Instructions: Take specimen to HMC Coag lab for processing.

Note: Order this test (PCCLOT) if "Protein C" is requested; unless the request specifies "Protein C Antigen", then order "PCAG".

Outside Laboratory: Centrifuge for 10 minutes, remove plasma & re-spin plasma for another 10 minutes. Decant & Freeze plasma (minimum 1.0 mL) @ -20°C to -80°C. Send frozen on dry

Performance

LIS Dept Code

Coagulation (COAG)

Performing Location(s)

HMC	Coagulation 206-520-4600 325 9th Ave, Rm # GWH-47, Seattle, WA 98104-2420

Frequency

Run Monday and Thursday. Reported by end of day.

Available STAT?

Billing & Coding

CPT codes

85303

LOINC

27819-2

Interfaced Order Code

UOW883

Interfaced Result Code

UOW883