ANALYTICAL AND CLINICAL-EVALUATION OF AN AUTOMATED CORTISOL ASSAY ON THE ACS-180(R)

Objective: To evaluate the analytical and clinical performance of an a utomated assay for serum cortisol on the ACS:180(R). Methodology: Anal ytical performance (sensitivity, precision, linearity, carryover, inte rference) was assessed using standard laboratory protocols. The values obtained on the ACS for protocol specimens were compared to those obt ained with a number of other automated assays on the ES300, TDX FL(X), and Stratus. Results: The assay exhibited within-run and total coeffi cients of variation of <4% and 8.1%, respectively. Good correlation wa s observed among all the assays for patient specimens for a.m. and p.m . cortisol values; however, the mean values for the ACS were approxima tely 10-15% higher than those with the ES300 and Stratus and 5% lower than those with the TDX FL(X). The reference range for all 4 assays as determined in a local population were higher than those claimed by th e manufacturers. Good agreement among the assays were obtained for pat ients undergoing dexamethasone suppression and ACTH stimulation tests. Conclusion: The cortisol assay on the ACS:180 is accurate and precise and provides results that are clinically comparable to other automate d assays. The random access capabilities of the instrument can facilit ate workstation consolidation for improved laboratory efficacy.