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Test ID PTNT Prothrombin G20210A Mutation, Blood

Useful For

Direct mutation analysis for the prothrombin (PT) G20210A allele should be reserved for patients with clinically suspected thrombophilia. There may be additional indications for direct PT G20210A mutation testing, such as in determining the duration of anticoagulation therapy of venous thromboembolism patients and screening for women contemplating hormone therapy.

Method Name

Direct Mutation Analysis

Reporting Name

Prothrombin G20210A Mutation, B

Specimen Type

Whole blood

Container/Tube: 

Preferred: Yellow top (ACD solution B)

Acceptable: EDTA or sodium citrate

Specimen Volume: Full tube

Collection Instructions:                                                               

1. Invert several times to mix blood.

2. Send specimen in original tube.

Additional Information: Can be combined with other molecular coagulation tests:

-MTHAC / 5,10-Methylenetetrahydrofolate Reductase A1298C, Mutation, Blood

-F5DNA / Factor V Leiden (R506Q) Mutation, Blood

-MTHFR / 5,10-Methylenetetrahydrofolate Reductase C677T, Mutation, Blood

-MTHP / 5,10-Methylenetetrahydrofolate Reductase C677T and A1298C Mutations, Blood

Forms:

1. New York Clients-Informed consent is required. Please document on the request form or electronic order that a copy is on file. An Informed Consent for Genetic Testing (Supply T576) is available in Special Instructions.

2. Coagulation Patient Information Sheet (T675) in Special Instructions

3. If not ordering electronically, complete, print, and send a Coagulation Test Request Form (T753) with the specimen (http://www.mayomedicallaboratories.com/it-mmfiles/coagulation-test-request-form.pdf)

Specimen Minimum Volume

1 mL in a 3-mL ACD tube

Specimen Stability Information

Specimen Type Temperature Time
Whole blood Ambient (preferred) 7 days
  Frozen  7 days
  Refrigerated  7 days

Clinical Information

Venous thromboembolism (VTE) is a syndrome of deep vein thrombosis and its complication, pulmonary embolism. The prothrombin (PT) G20210A mutation (F2 rs1799963) is a common polymorphism within the 3’ untranslated region of the prothrombin gene, affecting 1.5% to 3% of Caucasian Americans, especially persons of southern European ancestry. The PT G20210A allele is uncommon among African Americans (carrier frequency of 0.4%). The PT G20210A mutation is associated with a 3-fold increased risk of venous thromboembolism due to increased plasma prothrombin activity among carriers.

 

The PT G20210A gene mutation test is a direct mutation analysis of patient blood leukocyte genomic DNA. At present, there are no other methods of detecting this VTE risk factor except for direct mutation testing.

Reference Values

Negative

Cautions

This direct mutation analysis will not detect individuals with thrombophilia caused by mechanisms other than the prothrombin (PT) G20210A mutation. Special Coagulation Clinic, Thrombophilia Center, and/or Medical Genetics consultations are available for Mayo Clinic patients and may be especially helpful in complex cases or in situations in which the diagnosis is atypical or uncertain. Genetic counseling is recommended before testing asymptomatic family members.

Day(s) Performed

Monday through Friday; 12 p.m.

Report Available

3 days

Performing Laboratory

Mayo Medical Laboratories in Rochester

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.

CPT Code Information

81240-F2 (prothrombin, coagulation factor II) (eg, hereditary hypercoagulability) gene analysis, 20210G->A variant

 

NY State Approved

Yes