Monitoring of C0 and C2 blood concentrations of cyclosporine on the Roche Hitachi 902 analyzer

This work provided parameters to perform the widely used enzyme multiplied immunoassay technique (Emit) cyclosporine assay on a Hitachi 902 analyzer. Instrument settings were optimized to arrive at assay characteristics regarding precision, linearity, and lower limit of quantitation among 105 samples from renal transplant recipients receiving cyclosporine. We compared successive results with Emit on a Cobas Integra 400 analyzer with HPLC-UV. We validated a quantitation range of 20-500 ng/mL. For all parameters tested total imprecision <5%. Calibration stability was at least 30 days. The reagent cartridge in the instrument was stable for 2 months between runs. We observed good correlations with other analytical methods. The following equations were obtained: Hitachi 902 = 0.984 Cobas Integra + 2.097; r = 0.998 and Hitachi 902 = 1.019 LC-UV + 3.143; r = 0.974. The mean bias was 1.68% for C0 and 0.02% for C2 concentrations between Hitachi 902 and Cobas Integra 400. Overestimations of 5.61% for C0 and 8.81% for C2 levels assayed with Emit Hitachi 902 were observed compared with LC-UV. The proposed, validated protocol enhanced the versatility of the Emit assay for routine therapeutic drug monitoring. The Hitachi 902 analyzer is an acceptable option for evaluation of C0 and C2 blood cyclosporine concentrations in transplant recipients.