Comparison of a monoclonal antibody fluorescent polarization immunoassay with monoclonal antibody radioimmunoassay for cyclosporin determination in whole blood.

ABSTRACT

We have compared the whole blood concentrations of parent cyclosporin A (CsA) using monoclonal fluorescence polarization immunoassay (FPIA) and radioimmunoassay (RIA) as well as polyclonal FPIA in kidney, heart, and bone marrow transplant patients (n = 89). A good correlation was found between monoclonal FPIA and monoclonal RIA (r = 0.96) and a slightly worse one between polyclonal and monoclonal FPIA (r = 0.90). The interassay coefficient of variation was satisfactory for all the methods-less than 5% for monoclonal FPIA. The monoclonal FPIA assay with Abbott TDx appears to provide rapid, precise, and accurate measurement of parent CsA. It is therefore useful for therapeutic monitoring of CsA in whole blood in kidney, heart, and bone marrow transplant patients.