Coagulation assay with improved specificity to factor V mutants insensitive to activated protein C

Area of Science:

• Hematology
• Clinical Chemistry
• Genetics

Background:

• Factor V-Leiden is a common hereditary defect in the protein C pathway, increasing thrombophilia risk.
• Existing detection methods for factor V-Leiden have variable accuracy due to interference from other factors and therapies.
• Prevalence estimates for factor V-Leiden vary widely (20-60%) potentially due to detection method differences.

Purpose of the Study:

• To develop a novel coagulation assay for accurate factor V-Leiden detection.
• To create a method less susceptible to interference from other coagulation factors and anticoagulants.
• To improve the reliability of factor V-Leiden screening in thrombophilia diagnostics.

Main Methods:

• Developed a coagulation assay using factor V-deficient plasma to dilute patient samples.
• Initiated coagulation via intrinsic (APTT), extrinsic (PT), or intrinsic X activation (RVVT) pathways.
• Added activated protein C (APC) to assess factor V stability and clotting time prolongation.

Main Results:

• The new assay showed distinct clotting time prolongation patterns for factor V-Leiden carriers compared to normal plasma.
• The assay demonstrated improved specificity, with less interference from Protein S deficiency or high Factor VIII levels.
• Factor V-Leiden was detectable in patients on oral anticoagulation therapy, suggesting broader applicability.

Conclusions:

• The developed assay offers a more reliable method for detecting factor V-Leiden.
• This assay minimizes interference, enhancing diagnostic accuracy for thrombophilia.
• The method's effectiveness in patients on oral anticoagulation expands its clinical utility.