Gentamicin substrate-labeled fluorescent immunoassay containing monoclonal antibody.

The current substrate-labeled fluorescent immunoassay for gentamicin has been modified by substituting monoclonal antibodies for conventional antiserum to gentamicin. The standard curve generated with gentamicin monoclonal antibody was essentially linear from 0 to 12 micrograms/ml, could detect 0.4 micrograms of gentamicin per ml, and had overall intra- and interassay precision values (coefficients of variation) of 1.9 and 5.0%, respectively. The substrate-labeled fluorescent immunoassay produced with gentamicin monoclonal antibody gave results with clinical specimens comparable (r = 0.991) to those obtained with the commercially available substrate-labeled fluorescent immunoassay and also with an enzyme immunoassay, a radioimmunoassay, and a fluorescent immunoassay. This technologically state-of-the-art assay employs both a nonisotopic label and monoclonal antibodies. It offers excellent precision, sensitivity, lot-to-lot reproducibility, linearity, and reagent stability.