Ciba Corning ACS:180 testosterone assay evaluated.

A fully automated direct assay of testosterone has been developed for the Ciba Corning ACS:180 immunoassay system. We have evaluated this method and compared specimen results with those from the Diagnostic Products Corp. (DPC) and Medgenix direct assays and an in-house extraction assay. Accuracy of the method was assessed by measuring GC-MS-targeted serum pools. Within-assay im- precision was <6% and between-assay imprecision <9% over the concentration range examined. High concentrations of lipid caused an increase in the measured testosterone but other potential interferents were without effect. Recovery was quantitative but was affected by sex-hormone-binding globulin. The method was positively biased with respect to the DPC and Medgenix assays but negatively biased with the extraction assay. Measurement of the GC-MS-targeted serum pools showed the assay to overestimate recovery by approximately 13%. The ACS:180 assay is particularly attractive as a routine assay because it is fully automated, obtains the first result in only 15 min, and shows good assay performance.