Chemiluminescent enzyme immunoassay using beta-D-galactosidase as the label and the bis(2,4,6-trichlorophenyl)oxalate-fluorescent dye system.

A chemiluminescent enzyme immunoassay (EIA) using beta-D-galactosidase as the enzyme label is described in this report. The activity of beta-D-galactosidase, after separation of bound and free fractions, was measured using a coupled enzyme procedure: lactose and glucose oxidase were used as the substrate and coupling enzyme, respectively. Hydrogen peroxide generated from glucose was determined by the chemiluminescence reaction using the bis(2,4,6-trichlorophenyl)oxalate-fluorescent dye system. This assay system was applied to the EIA of phenytoin using beta-D-galactosidase as the label and assay sensitivity was increased about 10 times compared with the original method. This method may also be applied to other EIAs of digitoxin, alpha-fetoprotein and thyroid-stimulating hormone.