Testing for Factor V Deficiency

Sample Requirements and Handling

The International Society on Thrombosis and Haemostasis recommends collecting venous blood into 3.2% (0.105-0.109 mol/L) trisodium citrate at a 1:10 ratio for Factor V deficiency testing 1
Double-centrifuge the sample to ensure platelet-poor plasma with residual platelet count <10.0 × 10⁹/L, as recommended by the International Society on Thrombosis and Haemostasis 1
Test plasma within 4 hours of collection, or freeze at -20°C for ≤2 weeks or -70°C or below for >2 weeks, according to the International Society on Thrombosis and Haemostasis guidelines 1
Rapidly thaw frozen samples in a 37°C waterbath and mix thoroughly by gentle inversions before testing, as suggested by the International Society on Thrombosis and Haemostasis 1
The American Society of Hematology notes that icterus, hemolysis, and lipemia can interfere with coagulation assays, so ensure proper sample quality 1

The European Hematology Association advises against confusing Factor V deficiency testing with Factor V Leiden testing, as these are completely different conditions (deficiency vs. thrombophilia) 3
Factor V deficiency will prolong both PT and aPTT, whereas Factor V Leiden does not affect routine coagulation tests, according to the British Committee for Standards in Haematology 3