Predicting the outcome of short Synacthen test based on baseline cortisol levels: A single-centered retrospective cohort study at a tertiary care hospital in Sri Lanka.

This article focuses on evaluating baseline Cortisol levels as predictors of Short Synacthen Test (SST) outcomes to diagnose adrenal insufficiency (AI) and establish regional cut-off values, aiming to reduce the need for the SST. Conducted retrospectively at the National Hospital Kandy, Sri Lanka, the study analyzed 307 patients and found that baseline Cortisol strongly correlated with post-SST Cortisol, particularly at 30 minutes, with derived cut-offs (<135 nmol/L indicating AI and >381.5 nmol/L indicating normal adrenal reserve) allowing avoidance of up to 42% of SSTs. The 30-minute SST measurement demonstrated superior diagnostic performance compared to the 60-minute measurement, supporting a clinical approach where patients with intermediate baseline Cortisol levels undergo only a 30-minute SST. These findings suggest that initial baseline Cortisol testing can streamline AI diagnosis, though further multi-center validation is recommended.