Cyclosporine and metabolites (maded by FPIA Abbott TDx) and cyclosporine (maded by FPIA Abbott AxSyM) blood levels were assayed on 86 renal transplanted adult patients of any sex. Results were 3.26 times greater with TDx than with AxSyM (range=1,02-6,01, SD=0,99). That may be attributed to TDx antiserum cross-reactivity with cyclosporine metabolites. The wide variability in TDx/AxSyM rates (1,02-6,01) could be caused by interindividual differences on P-450 cytocrom-enzyme activities. It is suggested that differences in methods may require adjustments in therapeutic ranges.

drug monitoring; cyclosporine; kidney transplant