Rapid microassay of gentamicin, kanamycin, neomycin, streptomycin, and vancomycin in serum or plasma.

Abstract

Abstract With slight modifications in the standard agar diffusion methods, it was possible to determine the concentrations of antibiotics in 0.08 ml. samples of serum or plasma. The mean error was ±11 per cent and the results were available after incubation for 112 to 312 hours at 37 °C. Gentamicin, kanamycin, streptomycin, neomycin, or vancomycin were rapidly assayed, even in the presence of penicillins or cephalosporins which could be readily inactivated with a zinc-requiring, "broad-spectrum" β-lactamase. The method was particularly helpful for regulation of the therapy in patients with diminished renal function in whom estimation of dosage on the basis of renal function was less reliable.