Evaluation of a fully mechanised immunoassay--Enzymun-Test System ES 300--and comparison with in-house methods for 8 analytes.

The following analytes were determined with the automated enzyme immunoassay unit, Enzymun-Test System ES 300, and by routine in-house tests, and the results were compared: thyrotropin, free thyroxine, cortisol, immunoglobulin E, digoxin, digitoxin, insulin and carcinoembryonic antigen. The methods used for comparison included two radioimmunoassays, one with enzyme labelling, two with fluorescence enhanced enzyme reactions and 3 luminescence immunoassays. In most cases, the precision of the ES 300 lay between 2 and 5% in all assays in the concentration ranges of clinical interest. The inter-assay variation was almost identical to the intra-assay precision, which reflects the constancy of reagent quality and machine performance. The correlation between in-house and Enzymun-Test was excellent, even though the slope of the regression line was sometimes far from unity, due to the calibration materials used. ES 300 can be used as a stand alone unit and connected to a host computer. As a "walk-away" machine, it is suitable for laboratories with medium length series. It is a multi-batch analyser capable of taking 12 analytes and a maximal series length of 136 tubes excluding standards and controls.