Order to detect factor V Leiden variant.
- Patient Preparation
- Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).
- Specimen Preparation
- Transport 3 mL whole blood. (Min: 1 mL)
- Storage/Transport Temperature
- Unacceptable Conditions
- Plasma or serum; collection of specimen in sodium heparin tubes.
- Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
Characteristics: Factor V Leiden mutation is the most common cause of inherited thrombophilia and accounts for over 90 percent of activated protein C resistance. The expression of Factor V Leiden thrombophilia is impacted by coexisting genetic thrombophilic disorders, acquired thrombophilic disorders (malignancy, hyperhomocysteinemia, high factor VIII levels), and circumstances including: pregnancy, oral contraceptive use, hormone replacement therapy, selective estrogen receptor modulators, travel, central venous catheters, surgery, transplantation and advanced age.
Incidence: Approximately 5 percent of Caucasians, 2 percent of Hispanics, 1 percent of African Americans and Native Americans and 0.5 percent of Asians are heterozygous; homozygosity occurs in 1 in 5000 individuals.
Inheritance: Incomplete autosomal dominant.
Penetrance: Lifetime risk of thrombosis is 10 percent for heterozygotes and 80 percent for homozygotes.
Cause: A deleterious F5 gene mutation R506Q(1691G>A). Note: Standardized nomenclature for the Factor V Leiden mutation is c.1601G>A (p.Arg534Gln).
Clinical Sensitivity and Specificity: 99 percent.
Methodology: Polymerase chain reaction and fluorescence monitoring.
Analytical Sensitivity and Specificity: 99 percent.
Limitations:Diagnostic errors can occur due to rare sequence variations.F5 gene mutations, other than R506Q, will not be detected.
|Component Test Code*||Component Chart Name||LOINC|
|0097720||Factor V Leiden (F5) R506Q Mutation||21668-9|
- Activated protein C resistance mutation
- APC Resistance Mutation Detection
- FVL R506Q mutation testing