Figure 3. Investigations algorithm for suspected Cushing’s syndrome; CS – Cushing’s syndrome, ONDST – overnight dexamethasone suppression test, UFC – urinary free cortisol, LDDST – low dose dexamethasone suppression test, HDDST – high dose dexamethasone suppression test, BIPSS – bilateral inferior petrosal sinus sampling, PPNAD – primary pigmented nodular adrenocortical disease, AIMAH – ACTH-independent multinodular adrenal hyperplasia.