Clinical Application of SLFIA Method for Monitoring Plasma Concentration of Antiepileptics

Plasma concentrations of primidone, phenobarbital and phenytoin were assayed by AMES TDATM Kit (Miles-Sankyo Co., Ltd.), the newly developed Substrate-Labeled Fluorescent Immunoassay (SLFIA). The results were compared with those obtained by High-Pressure Liquid Chromatography (HPLC) method, where the SLFIA results showed high correlation with HPLC. The correlation coefficient was over 0.977 both in SLFIA and in HPLC and the coefficient variation was less than 6% in a spiked sample by the SLFIA method in the replicated analysis based on 147 plasma samples obtained from 144 epileptic patients given antiepileptics. The correlation coefficient obtained from the SLFIA method using the spiked sample was also over 0.998.SLFIA procedure in clinical application for determination of plasma concentrations has considerable advantages over hitherto available methods. This method requires only 50μl of plasma for a single determination, which may eliminate deproteinization and extraction steps. These results suggest that SLFIA is a simple method for monitoring plasma concentration of antiepileptics.