Comparison of three assay procedures for gentamicin determination

We examined 50 serum samples, submitted to our laboratory for gentamicin levels, by the enzyme multiplied immuno technique (EMIT), by a radioimmunoassay procedure and by a latex agglutination method. Significant differences in concentrations, rates of throughput, and costs between the latex agglutination and the other two procedures were observed. The precision of the assay ranged from 5.21 to 15.70%, whereas recovery values ranged from 83.8 to 110.0%. The latex agglutination procedure provided simplicity and speed at a relatively low cost. However, the significant analytical difference between this and the other two procedures indicates that the latex agglutination procedure is not adequate for measuring accurate gentamicin levels.