Comparative analysis of two rapid automated methods and a semiautomated version of the urease method for determining aminoglycoside concentrations in serum.

The Syva EMIT Autolab 6000 and the Abbott TDX automated methods for measuring serum aminoglycoside concentrations were compared with each other and with a new semiautomated version of the urease technique. Each was evaluated for accuracy, reproducibility, cost, and ease of use. All three methods gave satisfactory results, although the Abbott TDX was the most accurate. Both automated methods gave results within minutes, whereas the new urease method, which involved more initial manipulation, took 1.25 h to complete (mainly incubation time). There was no difference in accuracy of performance between experienced and inexperienced operators. The new urease method was much cheaper in terms of initial capital expenditure and in cost per test and needed no provision of manufacturer's back-up maintenance services. This could prove invaluable in situations where financial resources are at a premium. Otherwise, the Abbott TDX is currently our method of choice, and reasons for its preference to the EMIT system are listed.