Factor V Leiden (G1691A) Mutation, By PCR, Blood


Activated protein C resistance, which leads to thrombophilia, is due to a single mutation at nucleotide 1691 (CGA -> CAA) in the Factor V gene resulting in the replacement of the normal arginine at position 506 by a glutamine. This replacement makes Factor Va resistant to inactivation by Protein C. Factor V (not Va) is also a cofactor for protein C in the inactivation of factor VIIIa. This activity as a cofactor is lost as a result of the mutation. Thus, the mutation leads to factor Va and factor VIIIa resistance to inactivation by protein C. See Also Activated Protein C Resistance (Factor V Leiden), Plasma and Protein C Antigen Assay


This test is useful in the differential diagnosis of hereditary thrombophilia. Around 20% of heterozygotes and 40% of homozygotes develop thrombosis at an average age of 36 and 25 respectively. The relative risk of venous thrombosis for carriers of this mutation is estimated to be 5-10 fold increase for heterozygote and 50-100 fold increase for homozygote individuals.

Sample Type, Quantity & Conditions

2 ml EDTA Whole Blood Room Temperature

Special Precautions

Collect in EDTA vacutainer tube. Avoid contamination with DNA of phlebotomist. Avoid haemolysed samples. Do not freeze samples. Send tube unopened.

Normal Range

By Report

Open chat
Scan the code
Hello 👋
Can we help you?