Assess genetic risk for thrombosis.
- 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
- Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
Characteristics: The Factor XIII (F13A1), V34L sequence variant is a protective factor against pulmonary embolism, deep vein thrombosis, and myocardial infarction in Caucasians. It may also have a slight protective effect against coronary artery disease. Limited data suggests the V34L sequence variant may also be associated with idiopathic spontaneous subconjunctival hemorrhage (SSH), but this finding has not been confirmed.
Allele Frequency: Caucasian 0.27, African American 0.17, American Indian 0.29, Asian 0.01.
Inheritance: Autosomal dominant.
Cause: Homozygosity or heterozygosity for F13A1; V34L
Variant Tested: F13A1 c.103G>T; p.Val34Leu.
Clinical Sensitivity: Varies by ethnicity.
Methodology: Polymerase chain reaction and fluorescence monitoring.
Analytical Sensitivity and Specificity: 99 percent.
Limitations: Mutations in the F13A1 or F13B genes, other than the V34L sequence variant, are not evaluated. Diagnostic errors can occur due to rare sequence variations.
The protective effect of the V34L sequence variant has not been established for ethnicities other than Caucasian and may be altered by other genetic and non-genetic factors not assessed by this assay.
Counseling and informed consent are recommended for genetic testing. Consent forms are available online.
|Component Test Code*||Component Chart Name||LOINC|
|2003227||Factor XIII (F13A1) V34L Variant|
|2003228||Factor XIII Variant Specimen|