Orderable Name GNPRC Protein C Deficiency, PROC Gene, Next-Generation Sequencing, Varies

Ordering Guidance

This test should only be considered if clinical and family history, initial coagulation screens, and initial protein C activity and antigen tests indicate a diagnosis of antithrombin deficiency (see Testing Algorithm). This test does not measure protein C activity or antigen levels.

For assessment of protein C activity, order CFX / Protein C Activity, Plasma. If protein C activity is low, protein C antigen testing could help distinguish between type I and type II deficiencies; order PCAG / Protein C Antigen, Plasma.

For assessment of protein C antigen, order PCAG / Protein C Antigen, Plasma.

If genetic testing for hereditary blood clotting disorders using a larger panel is desired, a 16-gene comprehensive thrombosis panel is available; order GNTHR / Thrombosis Disorders, Comprehensive Gene Panel, Next-Generation Sequencing, Varies.

Testing for the PROC gene as part of a customized panel is available. For more information see CGPH / Custom Gene Panel, Hereditary, Next-Generation Sequencing, Varies.

Targeted testing for familial variants (also called site-specific or known variants testing) is available for variants identified in the PROC gene. See FMTT / Familial Variant, Targeted Testing, Varies. To obtain more information about this testing option, call 800-533-1710.

Shipping Instructions

Specimen preferred to arrive within 96 hours of collection.

Necessary Information

Rare Coagulation Disorder Patient Information is required. Testing may proceed without the patient information, however, the information aids in providing a more thorough interpretation. Ordering providers are strongly encouraged to fill out the form and send with the specimen.

Specimen Required

Specimen Type: Whole blood

Patient Preparation: A previous bone marrow transplant from an allogenic donor will interfere with testing. Call 800-533-1710 for instructions for testing patients who have received a bone marrow transplant.

Container/Tube:

Preferred: Lavender top (EDTA)

Acceptable: Yellow top (ACD)

Specimen Volume: 3 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send whole blood specimen in original tube. Do not aliquot.

Specimen Stability Information: Ambient (preferred) 4 days/Refrigerated

Forms

1. Rare Coagulation Disorder Patient Information (T824) is required.

2. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available:

-Informed Consent for Genetic Testing (T576)

-Informed Consent for Genetic Testing (Spanish) (T826)

3. If not ordering electronically, complete, print, and send an Coagulation Test Request (T753) with the specimen.

Useful For

Evaluating protein C deficiency in patients with a personal or family history suggestive of this hereditary thrombophilia

Confirming a diagnosis of autosomal dominant protein C deficiency with the identification of a known or suspected disease-causing alteration in the PROC gene

Confirming a diagnosis of autosomal recessive severe protein C deficiency with the identification of homozygous or compound heterozygous disease-causing alteration(s) in the PROC gene

Determining the disease-causing alteration(s) within the PROC gene to delineate the underlying molecular defect in a patient with a laboratory diagnosis of protein C deficiency

Prognosis and risk assessment based on the genotype-phenotype correlations

Ascertaining the variant status of family members related to an individual with a confirmed PROC variant for the purposes of informing clinical management and genetic counseling

Carrier testing for close family members of an individual with a diagnosis of autosomal recessive severe protein C deficiency

This test is not intended for prenatal diagnosis.

Testing Algorithm

The clinical workup for protein C deficiency should begin with special coagulation testing for protein C activity.

Genetic testing for protein C deficiency is indicated if:

-Protein C activity is less than 75% of normal (Note: reference range may vary depending on the locally established reference range)

-There is a clinical suspicion of hereditary thrombophilia and possible protein C deficiency due to family history or atypical clinical presentation

-Acquired causes of protein C deficiency have been excluded (eg, vitamin K deficiency, oral anticoagulation with coumarin compounds, liver disease, and intravascular coagulation and fibrinolysis/disseminated intravascular coagulation)

Method Name

Sequence Capture and Targeted Next-Generation Sequencing (NGS) followed by Polymerase Chain Reaction (PCR) and Sanger Sequencing

Specimen Type

Varies

Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type	Temperature	Time	Special Container
Varies	Varies

Reject Due To

All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Reference Values

An interpretive report will be provided.

Day(s) Performed