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Test 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.


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

Genetics Test Information

This test detects the F5 c.1601G>A; p.Arg534Gln variant (legacy R506Q).

Disease States

  • Factor V Leiden

Method Name

Direct Variant Analysis

Reporting Name

Factor V Leiden (R506Q) Mutation, B

Specimen Type

Whole blood

Specimen 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.

Method Description

An allelic discrimination assay is set up using TaqMan chemistry. End-products are analyzed using a real-time polymerase chain reaction instrument for genotype detection.(Package insert: TaqMan SNP Genotyping Assays. Applied Biosystems; 2014)

Day(s) Performed

Weekly

Report Available

3 to 5 days

Performing 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