Factor V HR2 Analysis

Compound heterozygosity for the factor V HR2 haplotype and the factor V Leiden mutation is associated with an increased risk for venous thrombosis as compared with heterozygosity for factor V Leiden alone. Some studies suggest that the HR2 haplotype alone is an independent thrombotic risk factor. The HR2 haplotype alone is associated with a two-fold increase in risk of venous thromboembolism, although further study is underway on this topic. Double heterozygosity for factor V Leiden and the factor V HR2 haplotype has not been associated with a significantly higher risk of early or late pregnancy loss than a heterozygous factor V Leiden.

Indications for Testing:

  • Personal history of two or more blood-clotting incidents
  • Deep vein thrombosis
  • Pulmonary embolism
  • Superficial venous thrombosis, phlebitis or thrombophlebitis
  • Family history of blood clots or factor V HR2

Sample Requirements

3 – 4 mL whole blood in purple top EDTA tube

Sample Handling

Blood samples stored overnight should be refrigerated or kept cold. Blood samples should never be frozen. Specimens being sent from outside facilities should be packaged with a cold pack according to standard medical safety practices. The specimen should be shipped by overnight priority [scheduled to arrive by Friday morning at the latest].

Shipping Address

Center for Human Genetics Laboratory
10524 Euclid Avenue, Sixth Floor
Cleveland, OH 44106

For local samples, please call Client Service (216-844-5227) to arrange for sample pick-up.

Turnaround Time

5 – 14 Days

CPT Code


Please submit a completed Molecular Requisition for each sample.

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