Hemostasis Reference Laboratory

DNA/Factor V Leiden (APC Resistance) Mutation

• Transaction Code: 3250-03
• CPT Code (Suggested): 83890, 83892, 83894, 83898, 83912

Factor V Leiden Mutation (hereditary APC Resistance; Factor V "Leiden", Dahlback, 1995) is a single point mutation of guanine (G) to adenine (A) at position 1691 of the factor V gene. This results in a substitution of glutamine for arginine at amino acid 506 resulting in Factor V Leiden and rendering it partially resistant to inactivation by APC. Their relative risks of venous thrombosis (vs. control) are about 7- and 80-fold (Rosendaal et al., 1995).

Method
The Method used for testing is PCR-RFLP. In brief, DNA is isolated from whole blood and subject to amplification with primers that recognize the polymorphic site. The amplified product is subjected to an enzyme which cleaves the amplified product at the mutation site and a gel electrophoresis enables a visual record of the results.

Test Details

• Sample Required: 5 ml Whole Blood EDTA (purple top)
• Test values: Homozygous glutamine (Gln⁵⁰⁶⁾; Abnormal values: Heterozygous or homozygous arginine (Arg⁵⁰⁶)
• Analytic Time: Run weekly (Tuesdays) on samples received Wednesday through Monday noon; abnormal tests are confirmed by repeating tests.