[Comparison of two methods for therapeutic drug monitoring: FPIA (TDx) and Emit]

Two procedures of immunoassay used for therapeutic drug monitoring were studied: fluorescence-polarization immunoassay using specific reagents and analyzer TDx ("Abbott") and enzyme immunoassay using specific reagents from "Syva" and analyzer Centrifichem 600 ("Baker Instr"). Control blood sera containing known concentrations of theophylline and quinidine as well as blood sera from patients treated with these drugs were analyzed within low, middle and high ranges. The data of both these procedures correlated at the high rate (r-0.93-0.96). Identity, reproducibility and accuracy of the theophylline and quinidine concentrations measurement using fluorescence-polarization immunoassay constituted 1.4-3.5%, 2.0-8.5% and 95-109%, respectively, thus satisfying the high requirements and were superior as compared with corresponding parameters of the enzyme immunoassay.