Prothrombin (Factor II, F2) c.*97G>A or 20210G>A Variant Analysis

CPT Code(s)

81240, G0452


Prothrombin, F2, Factor II, G20210A, c.*97G>A


Molecular Diagnostics Laboratory

Clinical Indication and Relevance

The assay is recommended in patients with venous thromboembolism (VTE) when the results will influence treatment and clinical management decisions. It is also useful in patients and certain asymptomatic relatives to reduce the risk of VTE through counseling about preventative measures in circumstances of elevated risk.


DNA is isolated from the patient sample and the prothrombin gene containing the c.*97G (20210G) variant site is PCR-amplified and analyzed using an allelic discrimination assay employing specific primers and TaqMan probes. Results are reported as normal, heterozygous variant or homozygous variant for the c. *97G>A F2 variant.

Minimum Specimen Requirements


  • Peripheral blood (PB): 3-5 mL, in purple top (EDTA) tube
  • Yellow top (ACD) tube also acceptable


Room temperature or 2-8°C (wet ice or cold packs). Do not freeze.

Room temperature: 8 hours. Refrigerated: 48 hours.

Unacceptable Samples
Serum or plasma; frozen PB or BM; clotted blood; severely hemolyzed samples.

Turnaround time

Five to seven working days

View Requisition Sheet