How to interpret a single cortisol measurement.

Adrenal insufficiency can present with non-specific clinical features. Therefore, a single cortisol measurement is often included in the biochemical work-up of an unwell child. This article aims to review the diagnostic utility of a single cortisol measurement by outlining the physiological, clinical and technical factors affecting result interpretation. Clinical scenarios are used to illustrate how this test may be used in different commonly encountered situations in general paediatrics, with the aim of minimising the frequency of inconclusive results.