Test Details
Prothrombin (Factor II) G20210A Genotype Test
Factor II (prothrombin) is a coagulation protein produced by the liver. The factor II genotype is a variant form of factor II with a change in one of the amino acids resulting in increased clot formation.1 The intended use for Prothrombin (Factor II) testing is as an aid in selection of appropriate thrombosis prevention regimens. The genetic test identifies individuals with defects in clotting factors, thus allowing the physician to determine the need for more aggressive thrombosis prevention measures for these individuals. Such therapy prevents life-threatening clots, especially those that travel from veins in the legs to the lungs (pulmonary emboli).
References:
- DeStefano V, Rossi E. Testing for inherited thrombophilia and consequences for antithrombotic prophylaxis in patients with venous thromboembolism and their relatives. Thromb Haemost. 2013 Oct;110(4):697-705.
Methodology
Real time polymerase chain reaction (PCR)
Patient Preparation
None
Preferred Specimen
1.0 mL whole blood collected in EDTA (Lavender Top)
Alternate Specimen
- Buccal swab
- Dried Blood collected on an AdvanceDx 100 card
Transport Temperature
Refrigerated (ship on frozen cold packs)
Stability
Refrigerated: 15 days
Lab Values
Prothrombin (Factor II) G20210A Genotype Test
Genotypes -/-, +/-, +/+
Clinical Significance
Prothrombin (Factor II) G20210A Genotype Test
Genotype -/-
normal risk of clot formation
Genotypes +/-
increased risk of developing clots, especially if on oral estrogen therapy
Genotype +/+
markedly increased risk of developing clots, especially if on oral estrogen therapy
Treatment Options
Prothrombin (Factor II) G20210A Genotype Test
Genotypes +/-, +/+: consider low dose aspirin treatment
