Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

The short ACTH stimulation test (250μg) is the dynamic test most frequently used to assess adrenal function. It is possible that a single basal cortisol could be used to predict the dynamic response, but research has been hampered by the use of different assays and thresholds.To propose a morning baseline cortisol criterion of three of the most commonly-used modern cortisol immunoassays - Advia Centaur (Siemens), Architect (Abbott) and the Roche Modular System (Roche) - that could predict adrenal sufficiency.Observational, retrospective cross-sectional study at two centres.Retrospective analysis of the results of 1019 SSTs with the Advia Centaur, 449 SSTs with the Architect, and 2050 SSTs with the Roche Modular System assay. Serum cortisol levels were measured prior to injection of 250μg Synacthen and after 30 minutes. Overall, we were able to collate data from a total of 3518 SSTs in 3571 patients.Using receiver-operator curve analysis, baseline cortisol levels for predicting passing the SST with 100% specificity were 358 nmol/l for Siemens, 336 nmol/l for Abbott and 506 nmol/l for Roche. Utilising these criteria: 589, 158 and 578 SSTs respectively for Siemens, Abbott and Roche immunoassays could have been avoided.We have defined assay-specific morning cortisol levels that are able to predict the integrity of the hypothalamo-pituitary-adrenal axis. We propose that this represents a valid tool for the initial assessment of adrenal function and has the potential to obviate the need for dynamic testing in a significant number of patients. This article is protected by copyright. All rights reserved.


Journal article


Clinical endocrinology

Publication Date



Department of Experimental Medicine, Sapienza University of Rome, Viale Regina Elena, 324, 00161, Rome, Italy.