Puvaneswaralingam S, Kjellbom A, Lindgren O, et al. - Given the significance of an accurate diagnosis of autonomous cortisol secretion (ACS) along with low specificity of cortisol ≥50 nmol/l after overnight dexamethasone suppression (cortisol_ONDST), researchers examined the value of ACTH following overnight dexamethasone suppression (ACTH_ONDST) and cortisol following a 2‐day dexamethasone suppression test (cortisol2‐DAYDST) as markers of HPA‐axis suppression during ONDST. They conducted a cross‐sectional study examining patients with adrenal incidentalomas and basal ACTH ≥ 2.0 pmol/l. Outcomes suggest the possible utility of ACTH_ONDST and ACTH‐ratio as markers of HPA‐axis suppression in the investigation of adrenal incidentalomas. ACS should be suspected in cases with Cortisol_ONDST ≥ 50 nmol/l with ACTH_ONDST < 0.6 pmol/l or ACTH‐ratio < 18%.