The concept of a competitive enzyme immunoassay that utilizes simultaneously the bound and the free analyte-enzyme conjugate (heterobifunctional conjugate) for signal generation in response to varying analyte concentrations in samples has been investigated. Two antigenic sites of the heterobifunctional conjugate are used in the assay for binding to immunoglobulins: the analyte derivative binds ...

"Immunoassay" defines the body of techniques which use the antibody (Ab) macromolecule, usually of the IgG class, for the detection and quantitation of an enormous range of simple and complex antigen (Ag) molecules. The success of the methods relies on both the specificity and formation constant of the Ab used, and the ability to detect the interaction between Ab and Ag. Sensitive assays in com...

We describe a gentamicin assay in which a peroxidase-gentamicin conjugate competes with gentamicin for binding to a gentamicin antibody adsorbed to a polystyrene solid phase. The assay can be completed in 30 min and requires 50 microliter of diluted serum. The precision and accuracy are equivalent to that of a radioimmunoassay technique and the reagents are stable for several months.

An enzyme immunoassay for tobramycin utilizing glucose 6-phosphate dehydrogenase was compared with the radioimmunoassay. The enzyme immunoassay for tobramycin was accurate, specific, and easily performed. It offers an alternative method for assaying aminoglycosides and could be used in institutions that use the enzyme immunoassay to assay other drugs.