DNA analysis for Factor V Leiden (FVL) & Prothrombin gene mutation (PT20210A)
Haematology Overview / Directory
Purpose of the test
Inherited resistance to activated protein C, associated with the factor V Leiden mutation G1691A has been shown to be present in 20-50% of individuals with a history of deep vein thrombosis (DVT). G to A transition at position 20210 in the 3’ untranslated region of the prothrombin gene has also been implicated in the pathogenesis of venous thrombosis with an incidence of 5-7% in patients with at least one confirmed episode of DVT.
Heterozygosity for the Prothrombin G20210A variant has been shown to increase the risk of venous thrombosis by up to 3 fold. (Prothrombin G20210A genotype G/A)
Heterozygosity for factor V Leiden mutation is associated with a 5-10 fold increased risk of thrombosis. (Factor V Leiden genotype G/A)
The presence of Homozygous Factor V Leiden (Factor V Leiden genotype A/A) has been shown to increase the risk of venous thrombosis by 50-100 fold.
Multiplex PCR with primers designed to detect the Factor V Leiden and the prothrombin polymorphisms/mutations, followed by restriction analysis, enables detection of both causative mutations and hence an estimation of the risk of thrombosis
Reference Range
Factor V Leiden Genotype: G/G = NORMAL
Sample Requirements
One EDTA sample
Storage and Transport
Sample to be sent directly to Haemostasis Laboratory and can be stored at room temperature or 2-8 degrees celcius whilst awaiting delivery.
Turnaround Time
The assay is run every week.
Contacts
Haemostasis Laboratory on 020 3299 9000 ext 2434
email: liz.ford@nhs.net
