Conversion of cardiac and liver transplant recipients from HPLC and FPIA (polyclonal) to an FPIA (monoclonal) technique for measurement of blood cyclosporin A.

In an effort to replace HPLC and FPIA (polyclonal) for whole blood determination of Cyclosporin A (CsA), this study examined the application of FPIA (monoclonal) in patients post cardiac and liver transplantation. The assay had a minimum detectable dose of 15 microg/L, an overall recovery of 97% and was linear to 1200 microg/L, and gave inter-assay precision values of < 5% (CV). On comparing FPIA (monoclonal) and HPLC for 59 cardiac transplant recipient blood samples, a correlation of FPIA (monoclonal) = 1.30 (HPLC) + 36.34, r = 0.96 was obtained. With liver transplant samples (n = 348), the correlation was FPIA (monoclonal) = 1.21 (HPLC) + 42.15, r = 0.98. Correlation on 131 cardiac transplant recipients gave FPIA (monoclonal) = 0.31 FPIA (polyclonal) + 43.97, r = 0.68. It is concluded that when converting from HPLC to FPIA (monoclonal) a positive bias of 21%-30% is observed, and in replacing FPIA (polyclonal) with FPIA (monoclonal), a negative bias of 50%-69% is seen with liver and cardiac patients respectively. These data indicate that therapeutic ranges should be re-established or adjustments in CsA dosing would be necessary.