COMPARISON OF HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY AND MONOCLONAL FLUORESCENCE POLARIZATION IMMUNOASSAY FOR THE DETERMINATION OF WHOLE-BLOOD CYCLOSPORINE-A IN LIVER AND HEART-TRANSPLANT PATIENTS

Conflicting conclusions have been drawn from comparisons of highperfor mance liquid chromatography (HPLC) and the Abbott Diagnostics monoclon al fluorescence polarization immunoassay (mFPIA) for cyclosporin. The aim of this study was to compare whole blood cyclosporin A (CsA) conce ntrations measured by both mFPIA and HPLC in liver and heart transplan t patients. One hundred and twenty-four liver and 62 heart transplant patient samples were assayed by both methods. Assay imprecision for bo th methods during the studies was <7% over the range 150-800 mu g/L. A t an HPLC-determined concentration of 100 mu g/L, mFPIA overestimated CsA by 60% (liver) and 77% (heart). At 300 mu g/L, the overestimation was 40% (liver) and 45% (heart). On this basis, the mFPIA is not inter changeable with HPLC.