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.