Factor II (Prothrombin), DNA Analysis

Whole blood or LabCorp buccal swab kit (buccal swab collection kit contains instructions for use of a buccal swab)

7 mL whole blood or LabCorp buccal swab kit

3 mL whole blood or two buccal swabs

Lavender-top (EDTA) tube, yellow-top (ACD) tube, or LabCorp buccal swab kit

Contributes to the risk assessment for venous thromboembolis thromboembolism (VTE) to better inform decisions regarding treatment and clinical management decisions of patients with relevant personal history of VTE and potential preventative care for patients with significant family history of VTE.

Variant analyzed: c.*97G>A, previously referred to as G20210A. Results must be combined with clinical information for the most accurate interpretation. Molecular-based testing is highly accurate, but as in any laboratory test, diagnostic errors may occur. False positive or false negative results may occur for reasons that include genetic variants, blood transfusions, bone marrow transplantation, somatic or tissue-specific mosaicism, mislabeled samples, or erroneous representation of family relationships.

This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.

Polymerase chain reaction (PCR); restriction enzyme digestion

Venous thromboembolism is a multifactorial disease influenced by genetic, environmental, and circumstantial risk factors. The c.*97G>A variant in the F2 gene is a genetic risk factor for venous thromboembolism. Heterozygous carriers have a 2- to 4-fold increased risk for venous thromboembolism. Homozygotes for the c.*97G>A variant are rare. The annual risk of VTE in homozygotes has been reported to be 1.1% per year. Individuals who carry both a *97G>A variant in the F2 gene and a c. 1601G>A (p.Arg534Gln) variant in the F5 gene (commonly referred to as Factor V Leiden) have an approximately 20-fold increased risk for venous thromboembolism. Risks are likely to be even higher in more complex genotype combinations involving the F2 c.*97G>A variant and Factor V Leiden.¹ Additional risk factors include but are not limited to: deficiency of protein C, protein S, or antithrombin III-, age, male sex, personal or family history of deep vein thromboembolism, smoking, surgery, prolonged immobilization, malignant neoplasm, tamoxifen treatment, raloxifene treatment, oral contraceptive use, hormone replacement therapy, and pregnancy. Management of thrombotic risk and thrombotic events should follow established guidelines and fit the clinical circumstance. This result cannot predict the occurrence or recurrence of a thrombotic event. Genetic coordinators are available for health care providers to discuss results and for information on how to order additional testing, if desired, at 1-800-345-GENE.