Comparison of gentamicin assays.

The reliability of the newly developed enzyme multiplied immunoassay technique (EMIT) for gentamicin with a radioimmunoassay (RIA) technique that utilizes a double antibody technique was compared. A split sample comparison was performed on 86 serum gentamicin levels from 35 patients. The Gilford System 4 and the Abbott Auto Log Gamma Counter were employed for the EMIT and RIA assays, respectively. Comparison of the two methods revealed good correlation (r = 0.954), slope (0.952), and an intercept of 0.017 over the range of the standard curve (1--16 microgram/ml). Within-run and between-run precision were comparable for both systems. Both assays have found widespread application for routine therapeutic monitoring of gentamicin. However, the EMIT gentamicin assay offers significant advantages in speed and simplicity while maintaining comparable accuracy and precision to that of the established RIA procedures.