What is the diagnosis for Factor V Leiden thrombophilia?

From the Guidelines

Diagnosis of Factor V Leiden thrombophilia is typically made through genetic testing, which identifies the R506Q mutation in the gene encoding coagulation Factor V.

Key Points to Consider

• The diagnosis is often considered in patients with a history of idiopathic venous thromboembolism (VTE), particularly those with a strong family history of thrombotic disease, or those who have experienced recurrent VTE 1.
• Testing for Factor V Leiden is recommended in certain circumstances, including:
  • Age <50 with any venous thrombosis
  • Venous thrombosis in unusual sites
  • Recurrent venous thrombosis
  • Venous thrombosis and a strong family history of thrombotic disease
  • Venous thrombosis in pregnant women or women taking oral contraceptives
  • Relatives of individuals with venous thrombosis under age 50
  • Myocardial infarction in female smokers under age 50 1.
• The identification of Factor V Leiden heterozygosity does not necessarily change the therapeutic approach to venous thrombosis or subsequent prophylaxis in most patients. However, testing can identify individuals with increased recurrence risk who may benefit from long-term antithrombotic therapy 1.
• Factor V Leiden homozygosity is associated with a higher risk of recurrent venous thrombosis, and lifetime antithrombotic prophylaxis may be considered for these individuals after a thrombotic event 1.

From the Research

Diagnosis of Factor V Leiden Thrombophilia

The diagnosis of Factor V Leiden thrombophilia can be made through the following methods:

• Activated Protein C resistance assay, a coagulation screening test 2
• DNA analysis of the F5 gene, which encodes the Factor V protein 2, 3
• Screening for activated protein C (APC) resistance, followed by testing for the Factor V Leiden mutation if positive 3

Laboratory Testing

Laboratory testing for Factor V Leiden is important for the diagnosis and management of thromboembolic disorders 4. The preferred laboratory testing methods include:

• DNA analysis for the Factor V Leiden mutation
• Activated Protein C resistance assay

Clinical Utility

The clinical utility of Factor V Leiden testing includes:

• Defining those patients who should be tested for FVL 4
• Defining the therapeutic, prophylactic, and management ramifications of FVL testing in affected individuals and their family members 4
• Identifying individuals with an increased risk of venous thromboembolism 2, 5, 6