DNA/Factor V Leiden (APC Resistance) Mutation

• Transaction Code: 3250-03
• CPT Code (Suggested): 83890, 83896x2, 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).

This polymorphism is determined by real-time PCR (gene amplification) using LightCycler analysis Both heterozygous and homozygous Factor V Leiden individuals can be distinguished.

Method
DNA is isolated from whole blood and subjected to amplification (PCR). The test is performed on the Light Cycler instrument employing fluorogenic reagents (FRET) specific for the Factor V or Factor II mutations. Determination of the genotype is performed by melting curve analysis.

Test Requirements

• 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.