Summary
The currently used activated Protein C resistance test demonstrated to be of limited
diagnostic value for the detection of the mutant Factor V Leiden. Moreover, this assay
is not useful for patients under anticoagulant therapy. A modification of the APC
resistance test, applying Factor V deficient plasma is described which demonstrates
a specificity and sensitivity of 1.0. The superiority of the modified APC resistance
test over the existing APC resistance test was verified by genotyping.
For that purpose, the Amplification Refractory Mutation System (ARMS) was applied
to the detection of the G to A mutation at position 1691 in the gene encoding coagulation
Factor V. The mutation at that position could be easily detected by using each of
two allele-specific oligonucleotide primers concomitantly with one common primer in
two separate polymerase chain reactions, thereby amplifying a fragment of 186 base-pairs
of the Factor V gene.