Table 1.

Summary of dynamic tests

Test	Result	Interpretation
1 mg overnight DST	Morning cortisol 258 nmol/L	Failure to suppress cortisol secretion
	(normal suppression  < 50 nmol/L)
24 h UFC	987 nmol/L	Values greater than 3 times ULN are highly suggestive of Cushing’s syndrome
	(Ref. 0–83 nmol/L)
CRH test	ACTH 0 mins 60 pg/ml	Greater than 50 % rise in ACTH, suggestive of Cushing’s syndrome
	Cortisol 0 mins 756 nmol/L
	ACTH 15 mins 104 pg/ml
	Cortisol 15 mins 1126 nmol/L
IPSS (CRH augmented)	ACTH values 5 mins post CRH	No central to peripheral gradient
	Left petrosal 166 pg/ml
	Right petrosal 92 pg/ml
	peripheral 77 pg/ml
IPSS (CRH augmented)	ACTH values 5 mins post CRH	Marked central to peripheral gradient (PPV 98 %)
	Left petrosal >2100 pg/ml
	Right petrosal 271 pg/ml	Lateralising to left (accuracy 69 %) [28, 29]
	peripheral 176 pg/ml

DST- Dexamethasone suppression test

UFC – Urinary free cortisol

CRH – Corticotropin-releasing hormone

ACTH- Adrenocorticotrophic hormone

IPSS – Inferior petrosal sinus sampling

ULN - Upper limit of normal

PPV-positive predictive value for diagnosis of pituitary-dependant Cushing’s syndrome (Cushing’s disease)