Lab Dept:

Coagulation

Test Name:

PROTEIN C CHROMOGENIC

General Information

Lab Order Codes:

PRC

Synonyms:

Protein C Activity Assay; Protein C Immunologic Assay

CPT Codes:

85303 – Clotting inhibitors or anticoagulants; Protein C activity

Test Includes:

Protein C activity

Logistics

Test Indications:

Protein C, along with its cofactor Protein S, acts as a potent anticoagulant by destroying activated Factors 5 and 8. It also stimulates the fibrinolytic system. It is Vitamin K dependent, therefore it is decreased in coumadin therapy or Vitamin K deficiency. Protein C deficiency is a risk factor for thromboembolism. Severe deficiency may cause purpura fulminans in neonates. Incident to a thrombotic event, both procoagulant and regulatory coagulation proteins may be lower than basal state due to excessive consumption or higher than basal state from reactive overproduction. Therefore, it is best not to test for Protein C deficiency during an acute thrombotic event. The Protein C antigen test determines the amount of the molecule present, not its functionality. The Protein C Chromogenic (activity) assay determines the functionality. Therefore, the Protein C Chromogenic (activity) assay is the preferred method.

Lab Testing Sections:

Coagulation (Minneapolis Campus)

Phone Numbers:

Minneapolis:

Saint Paul:

612-813-6280

651-220-6550

Test Availability:

Monday – Friday (0630–1500)

Turnaround Time:

1 – 3 days

Special Instructions:

Elective testing for Protein C deficiency is best done at least 30 days after cessation of Coumadin® therapy.

Protein C may be reduced during an acute event (thrombotic, surgical, etc.) therefore it is preferable not to test for it during this time. However a normal value at the time of an acute event excludes a congenital deficiency.

Specimen

Specimen Type:

Whole blood

Container:

Light Blue top (Buffered Na citrate 3.2%) tube

Draw Volume:

2.7 mL blood in a 3 mL tube (Minimum: 1.8 mL in a 2 mL tube)

Processed Volume:

Minimum 1.8 mL (plasma)

Collection:

A clean venipuncture is essential.

If the patients hematocrit is >55%, call the laboratory for a special tube. Fill tube completely.

Mix thoroughly by gentle inversion.

Special Processing:

Lab Staff: All testing will be performed on the Mpls campus.

St.Paul Lab: Send whole blood specimens to Mpls. For processing via courier. Must be processed within 4 hours of collection. Contact Mpls prior to sending specimen.

Patient Preparation:

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

Sample Rejection:

Improper tube; clotted sample; underfilled tube; mislabeled or unlabeled specimens

Interpretive

Reference Range:

Age:

Range (%):

Newborn

14 - 42%

1 - 4 days

26 - 44%

5 - 29 days

31 - 53%

30 - 89 days

32 - 54%

90 - 179 days

41 - 67%

180 - 364 days

48 - 70%

1 - 5 years

40 - 92%

6 - 10 years

45 - 93%

11 - 16 years

55 - 111%

17 years and older

70 - 140%

Critical Values:

N/A

Limitations:

Coumadin® will lower Protein C.

Berichrom® Protein C detects the amidolytically active portion of the activated Protein C, including the non-carboxilated molecules synthesized in vitamin K deficiency. Thus, in conditions of vitamin K deficiency, a higher Protein C activity is found with Berichrom® Protein C than when using the coagulometric method. To obtain a complete picture of a Protein C deficiency, it is therefore advisable to also use the coagulometric method of the antigenic determination technique.

Methodology:

Protein C in the patient sample is activated by a specific snake venom activator. The resulting Protein C(a) is assayed in a kinetic test by measuring the increase in absorbance at 405nm.

References:

Siemens Berichrom Protein C package insert (May 2008) OUVV G15 E0501 (699), Siemens Healthcare DiagnosticsInc.,Newark, DE

Control Plasma N package insert (December 2007) Siemens Healthcare Diagnostics, Newark, DE

Control Plasma P package insert (December 2007) Siemens Healthcare Diagnostics, Newark, DE

Application Sheets for Protein C with Berichrom Protein C on BCS and BCS XP

BCS System Instruction Manual

BCS XP System Instruction Manual

Thrombophilia Powerpoint presentation Kandice Kottke-Marchant M.D. PhD. http://aniaracorp.s3.amazonaws.com/PhyFiles/Thrombophilia2/Marchant_medium.wmv

An Algorithmic Approach to Hemostasis Testing Kottke-Marchant (2008) CAP Press

Andrew M, Paes B, Milner R, et al, “ Development of the Human Coagulation System in the Full-Term Infant,” Blood, 1987,70(1):165-72

Andrew M, Vegh P, Johnston M, et al, “Maturation of the Hemostatic System During Childhood,” Blood,1992, 80(8):1998-2005

Updates:

2/6/2012: Test moved from referral to Fairview University to being performed at Children’s Laboratory.