Gentamicin assay: comparison of an adapted EMIT method and an RIA method

The EMIT technique for gentamicin assay adapted to the Centrifichem-300 system was compared with an established RIA procedure. EMIT results correlated very well with the results obtained by the RIA method (r = 0.976, N = 48). For the adapted EMIT assay, the interassay coefficient of variation was 4-8% and for the RIA method 6-14%. Several possible interfering agents were investigated, of which only carbenicillin showed interference in both assays. Our data indicate that the EMIT technique exhibits adequate precision and accuracy for routine gentamicin determinations.