Fluoroimmunoassay of serum gentamicin

Abstract

Flu?roimmunoassay methods permit rapid, reliable and technicaly simple estimation of gentamicin at levels of clinical significance in mlcrolitr~am?~ts of se~um sample~. The reagents required are fluorescein-labelled gentamicin, which is easily and economically prepared and has indefinite shelf life, and anti-gentamicin serum. All methods are based on competitive binding to antiserum between labelled and unlabelled gentamicin, but because of the versatility of the fluorescence technique, various assay modes are possible. When assay of gentam~cin.is performed to determine apprioriate clinical dosage the preferred method is the "quenching fluoroimmunoassay" in which determinations are made by means of conventional fluorimetry of unseparated immunoassay incubation mixtures. Assay time for this technique is of the order of 10 minutes per sample. When extreme sensitivity (10 ng/ml gentamicin) is necessary, the fluorescein groups of the labelled gentamicin may be conveniently radioiodinated to provide gamma-labelled material suitable for "radiofluoresceinimmunoassay". In this instance total assay time is about 4 hours.

Fluoroimmunoassay of Alphafetoprotein (AFP) in Amniotic Fluid

“…Current methods include immunodiffusion, counter-immunoelectrophoresis, enzyme immunoassay, and radioimmuncassay (Chard, 1978). Though fluoroimmunoassay (FIA) has been applied to a number of antigens (Shaw et al, 1977;Chard and Sykes, 1979), it has not so far been used for AFP. We describe here the development of a separation FIA for amniotic fluid AFP.…”

Enzyme Immunoassay: A Review

“…Non-isotopic labels used include bacteriophages (Haimovich et al, 1970), erythrocytes (Alder and Chi-Tan, 1971), stable free radicals (Leute et al, 1972), chemiluminescent labels (Schroeder et al, 1976), fluorescent groups (Shaw et al, 1977;Ullman et al, 1976;Miller, 1979) and enzymes.…”