Double-antibody fluorescence immunoassay of tobramycin.
This heterogeneous assay for tobramycin involves fluorescein-labeled tobramycin, which competes with native unlabeled tobramycin for anti-tobramycin binding sites. Bound and free labeled antigen are separated by precipitation with a second antibody. Fluorescence intensity of the resuspended precipitate is inversely proportional to native tobramycin concentration. Background interference was consistently about 10% of the total fluorescence precipitated. Assay sensitivity was sufficient to detect nanogram quantities of tobramycin per assay tube. Correlation coefficients (r) were 0.96 and 0.98 for comparisons of this assay with a microbiological assay and a radioimmunoassay, respectively. Mean analytical recovery was 101% and the CV was less than 10% throughout the therapeutic range.
D000900:Anti-Bacterial Agents / Q000097:blood*; D005452:Fluoresceins; D005455:Fluorescent Antibody Technique; D006801:Humans; D007106:Immune Sera; D014031:Tobramycin / Q000097:blood*
D000900:Anti-Bacterial Agents; D005452:Fluoresceins; D007106:Immune Sera; D014031:Tobramycin