Table 2. Comparison of the ES, AACE, PS, and ACG diagnostic recommendations.

ES: Endocrine Society; AACE: American Association of Clinical Endocrinologists; PS: Pituitary Society; ACG: Acromegaly Consensus Group; IGF-1: insulin-like growth factor; GH: growth hormone; TRH: thyrotropin-releasing hormone; GnRH: gonadotropin-releasing hormone; OGTT: oral glucose tolerance test; MRI: magnetic resonance imaging; CT: computed tomography

Diagnostic criteria/tests	ES	AACE	PS	ACG
IGF-1	First test of choice	First test of choice	First test of choice	First test of choice
GH as an initial diagnostic test	Not recommended	To be interpreted in the clinical context	Not recommended	Not recommended
OGTT-induced GH suppression	Confirms diagnosis	Confirms diagnosis. Nadir of GH suppression <1 advised to increase sensitivity	Confirms diagnosis. Physiological factors can confound results	Confirms diagnosis (it is recommended that 75 g be used to achieve a level of standardization)
Other biochemical tests	Not mentioned.	IGF-binding protein-3 or TRH tests are explicitly named to be irrelevant	IGF-binding protein 3 or acid-labile subunit can be used to evaluate equivocal GH and IGF-1 results	TRH and GnRH stimulation tests of GH secretion have been used as a second-tier evaluation but are not recommended due to the risk of side effects
Radiological tests	MRI/CT scan of the pituitary gland	MRI/CT scan of the pituitary gland	MRI/CT scan of the pituitary gland	MRI/CT scan of the pituitary gland
Visual tests	Recommended if the optic chiasm is involved	Recommended if the optic chiasm is involved	Recommended if the optic chiasm is involved	Recommended if the optic chiasm is involved
Other tests	None recommended	Prolactin levels and pituitary function tests	None recommended	None recommended