Table 5. Biochemical tests available in Brazil for diagnosis of adult growth hormone (GH) deficiency (AGHD).

Test	Protocol	Diagnosis criteria	Advantages	Considerations
Insulin tolerance test (ITT)	0.1 U/kg IV of regular insulin; measure glucose and GH at baseline and 30, 60, 90, and 120 minutes after insulin	GH peak < 3 μg/L (< 5 μg/L in the transition period)	Gold standard May allow simultaneous assessment of hypothalamic-pituitary-adrenal axis	Risk of serious adverse events Requires supervision Contraindicated in elderly individuals and patients with neurologic or cardiac disorders
Glucagon stimulation test (GST)	Glucagon 1 mg IM (1.5 mg for patients > 90 kg); measure glucose and GH at baseline and every 30 minutes after glucagon for 3–4 hours	GH peak < 3 μg/L (< 1.0 μg/L in overweight/obese individuals)	Glucagon is readily available May allow simultaneous assessment of hypothalamic-pituitary-adrenal axis	Adverse effects (nausea, vomiting, headache) Requires better standardization of time points and cut-off values
IGF-I	None	Below the lower limit of normal (adjusted for age)	Simple	A normal value does not exclude AGHD

IV: intravenous; IM: intramuscular.