A highly specific functional test for factor V leiden: A modified tissue factor assay for activated protein C resistance.
We compared the sensitivity and specificity of a tissue factor-based assay (FVR) with the addition of a phospholipid/silica preparation, to the commercially available aPTT-based method, APCR (CoatestTM), and a modified aPTT-based method (APCM) which utilized factor V-depleted plasma, for the detection of the factor V Leiden mutation. A total of 110 patients were included in this study. This included 32 patients on coumadin therapy, 7 patients on heparin therapy, 5 patients on both anticoagulants therapy, and 24 patients who were positive for anticardiolipin antibody (ACL) and/or lupus inhibitor (LI). Our data demonstrate that the FVR is not affected by anticoagulation treatment or ACL/LI antibodies, whereas in the APCR method, 33 patients cannot be determined either due to the anticoagulant therapy or presence of the ACL and/or LI. With the APCM method, the clotting endpoint could not be determined in 1 patient due to the presence of a strong LI. The additional phospholipid/silica material utilized in the FVR enhanced the APC degradation of factor Va and therefore sharpened the demarcation between the factor V Leiden-positive and -negative patients. The sensitivity for the APCR, APCM and FVR was 42, 97 and 100% respectively. The specificity for the APCR, APCM and FVR was 94, 96 and 100% respectively.
Arkel
Y S
YS
Blood Disorder Center for Hemostasis and Thrombosis, Overlook Hospital, Summit, N.J., USA.
Ku
D
D
Kamiyama
M
M
Pajaro
R
R
Alder
H
H
Marchand
A
A
D020016:Activated Protein C Resistance / Q000097:blood / Q000175:diagnosis; D017153:Antibodies, Anticardiolipin / Q000502:physiology; D016736:Antiphospholipid Syndrome / Q000235:genetics; D001780:Blood Coagulation Tests / Q000379:methods*; D005165:Factor V / Q000032:analysis* / Q000235:genetics; D006801:Humans; D007202:Indicators and Reagents; D007616:Kaolin; D016682:Lupus Coagulation Inhibitor / Q000502:physiology; D009154:Mutation; D010314:Partial Thromboplastin Time; D010743:Phospholipids; D016133:Polymerase Chain Reaction; D012016:Reference Values; D012680:Sensitivity and Specificity; D012822:Silicon Dioxide; D013925:Thromboplastin / Q000032:analysis
D017153:Antibodies, Anticardiolipin; D007202:Indicators and Reagents; D016682:Lupus Coagulation Inhibitor; D010743:Phospholipids; C095381:factor V Leiden; D007616:Kaolin; D012822:Silicon Dioxide; D005165:Factor V; D013925:Thromboplastin