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Test Name:
Factor V Leiden Mutation, by PCR
- SBMF No:
36001 - Performance Lab Name:
Flow Cytometry/Molecular Pathology - Test Mnemonic:
F5-LEIDEN - ABN:
Required – Not FDA-Approved - CPT Code:
83890; 83896x2; 83898; 83912 - LOINC Code:
21667-1 - Also See:
25185 Activated Protein C Resistance - Spec Type:
Whole blood - Spec Container:
Lavender top (EDTA), Pale Yellow top (ACD-B) or Light Blue top (3.2% buffered sodium citrate) tube - Pref Vol:
7.0 mL - Min Vol:
3.0 mL - Fasting:
No - Spec Collect:
Routine venipuncture
Avoid traumatic puncture - Spec Process:
Gently invert tube to mix blood with the anticoagulant
Do not centrifuge
Do not remove plasma from cells
Forward entire tube of unprocessed whole blood to the laboratory - Spec Store Transport:
Refrigerated - Spec Stability:
24 hours room temperature (20-30°C)
5 days refrigerated (2-8°C) - Spec Reject:
Severely hemolyzed specimen - Methodology:
Polymerase Chain Reaction (PCR) - Use:
Evaluating risk of inherited venous thrombosis - Clinical Significance:
Factor V Leiden is more resistant to proteolytic degradation by Activated Protein C (APC) and is the most common cause of inherited venous thrombosis in the Caucasian population. The mode of inheritance is autosomal dominance. The mutation has been found in northern and southern Europe with a three to five percent prevalence rate. It has also been found in Arab populations. This mutation is apparently absent in African, Asian, and Australian aboriginal populations. Persons who are heterozygous for Factor V Leiden have a relative risk of venous thrombosis that is five- to ten-fold higher than the general population. Those who are homozygous have an estimated 80-fold increased risk of venous thrombosis. Risk of thrombosis is high in certain conditions such as pregnancy, immobilization, surgery, and use of oral contraceptives. The advantage of genetic analysis for this mutation over plasma screening is that the results of genetic analysis can indicate presence of APC resistance in patients receiving anticoagulants or patients who have inhibitors for the activated partial thromboplastin time (APTT) test. - Reference Range:
Factor V Leiden Mutation, by PCR
Negative (no mutation is present)Interpretive Data:
Negative: The patient is negative for Factor V Leiden, R506Q polymorphism; mutations in other genes or other mutations in the factor V gene that may cause APC resistance and venous thrombosis are not ruled out.
Homozygous: The patient is homozygous for Factor V Leiden, R506Q polymorphism and may have a 50-fold increased risk for venous thrombosis.
Heterozygous: The patient is heterozygous for Factor V Leiden, R506Q polymorphism and may have a 5-fold to 10-fold increased risk for venous thrombosis. - Day Run:
Mon, Fri - Time Run:
8:00 am - Time Reported:
48 hours - Test Type:
COAGULATION
