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HelpTest Code F5DNA Factor V Leiden (R506Q) Mutation, Blood
Ordering Guidance
This assay will only detect the F5 c.1601G>A; p.Arg534Gln (rs6025) variant associated with factor V Leiden thrombophilia. To detect other pathogenic alterations in the F5 gene of a patient with a laboratory diagnosis of coagulation factor V deficiency, order F5NGS / F5 Gene Next Generation Sequencing, Varies.
This assay will not will not detect alterations in individuals with activated protein C (APC)-resistance caused by mechanisms other than the F5:c.1601G>A, p.Arg534Gln variant. Coagulation-based activated protein C (APC)-resistance ratio (mixing with factor V-deficient plasma) is recommended as the initial screening assay for APC-resistance. Depending on the assay system, the APC-resistance ratio may be indeterminate for patients with a lupus anticoagulant or extremely high heparin levels. For more information, see APCRV / Activated Protein C Resistance V (APCRV), Plasma or APCRR / Activated Protein C Resistance V (APCRV), with Reflex to Factor V Leiden, Blood and Plasma.
Specimen Required
Patient Preparation: A previous bone marrow transplant from an allogenic donor will interfere with testing. Call 800-533-1710 for instructions for testing patients who have received a bone marrow transplant.
Container/Tube:
Preferred: Lavender top (EDTA)
Acceptable: Yellow top (ACD solution B), light-blue top (sodium citrate)
Specimen Volume: 3 mL
Collection Instructions:
1. Invert several times to mix blood.
2. Send specimen in original tube. Do not aliquot.
Forms
1. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available in Special Instructions:
-Informed Consent for Genetic Testing (T576)
-Informed Consent for Genetic Testing-Spanish (T826)
2. Coagulation Patient Information (T675) in Special Instructions
Useful For
Patients with clinically suspected thrombophilia and:
1. Activated protein C (APC)-resistance either proven or suspected by a low or borderline APC-resistance ratio
or
2. A family history of factor V Leiden
Special Instructions
Method Name
Direct Variant Analysis
Reporting Name
Factor V Leiden (R506Q) Mutation, BSpecimen Type
Whole bloodSpecimen Minimum Volume
1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Whole blood | Ambient (preferred) | 14 days | |
| Frozen | 14 days | ||
| Refrigerated | 14 days |
Reject Due To
| Gross hemolysis | OK |
| Gross lipemia | OK |
| Extracted DNA | Reject |
Clinical Information
Venous thromboembolism includes deep vein thrombosis and its complication, pulmonary embolism. Plasma from 12% to 20% of venous thromboembolism patients is resistant to the anticoagulant effect of activated protein C (APC resistance). Essentially all patients with hereditary APC resistance have the factor V Leiden, F5 c.1601G>A, p.Arg534Gln (legacy R506Q) variant.
Reference Values
Negative
Interpretation
The results will be reported as:
-Negative for the F5 c.1601G>A, p.Arg534Gln variant
-Heterozygous for the F5 c.1601G>A, p.Arg534Gln variant
-Homozygous for the F5 c.1601G>A, p.Arg534Gln variant
Cautions
This assay will only detect the genetic basis for activated protein C (APC)-resistance due to the F5 c.1601G>A, p.Arg534Gln variant. This assay will not detect the genetic basis for APC resistance due to other variants nor the acquired APC resistance.
This assay will not detect alterations in individuals with thrombophilia caused by mechanisms other than the F5 c.1601G>A, p.Arg534Gln variant.
Rare single nucleotide variants under the primers can cause preferential amplification of one allele. In many cases, there is no indication that this interference has occurred. Consequently, the analysis could be done on data from only one allele, which may cause a false-negative result or an incorrect allele frequency (homozygous instead of heterozygous).
Discrepancy between the APC resistance assay and the DNA based F5 c.1601G>A, p.Arg534Gln assay may be observed in patients receiving allogenic stem cell transplants or liver transplants.
Consultations with the Mayo Clinic Special Coagulation Clinic Thrombophilia Center, and/or Medical Genetics are available and may be especially helpful in complex cases or in situations in which the diagnosis is atypical or uncertain. Genetic counseling is recommended before testing asymptomatic family members.
Day(s) Performed
Weekly
Report Available
3 to 5 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
81241
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| F5DNA | Factor V Leiden (R506Q) Mutation, B | 21668-9 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 21838 | Factor V Leiden (R506Q) Mutation, B | 21668-9 |
| 21839 | F5DNA Interpretation | 69049-5 |
| 21841 | F5DNA Reviewed By | 18771-6 |