Factor V Leiden is the most common genetic predisposition risk to venous thromboembolisms. Venous thrombosis is a worldwide health problem resulting in significant illness and death. Both genetic as well as environmental factors,  e.g. smoking and oral contraceptives, contribute to the incidence of the disease. A G1691A mutation (Arg506Gln) in the Factor V gene (chromosome 1q23) leads to a resistance to the anticoagulation factor protein C (APC-resistant). Individuals that carry one copy of  this mutation have a 5- to 10-fold increase risk for venous thrombosis; individuals that carry two of these mutations have a 50- to 100-fold increase risk for venous thrombosis. Between 3% and 7% of the US population are carriers of the mutation and at increased risk. Prophylactic anticoagulation therapy should be considered for carriers in high-risk situations such as surgery.

• To determine the potential cause of unexplained thrombosis in children or adults.
• Patients undergoing surgery especially the potentially high-risk class of women taking estrogen supplements.
• Evaluation of individuals before initiation of oral contraceptives.

• Testing may be combined with testing for Prothrombin, MTHFR, & HPA1 in a Thrombosis Risk Panel.

• PCR amplification of the region including the G1691A mutation, followed by mutation specific restriction enzyme digestion.

• Blood EDTA (purple top) tubes:  

            Newborn: minimum 1-2 mL          

            Child/Adult: prefer 2 tubes of 3-5 mL

• Prenatal testing: Please contact the laboratory for instructions.

TURNAROUND TIME:     8 working days

CPT CODES: