Abstract
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 15μg/ L, an overall recovery of 97% and was linear to 1200μg/ 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 reestablished or adjustments in CsA dosing would be necessary. J. Clin. Lab. Anal. 12:337–342, 1998. © 1998 Wiley‐Liss, Inc.
Keywords: transplantation, immunosuppressive drugs, therapeutic drug monitoring, intermethod comparison, fluorescence polarization immunoassay
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