Diagnosis of adult growth hormone deficiency: still a matter of debate.

The diagnosis of GH deficiency (GHD) in adults is established by laboratory testing in patients with an appropriate clinical history of hypothalamic pituitary disease. As the measurement of IGF-I and IGFBP-3 levels as well as the spontaneous GH secretion are not considered reliable parameters, the diagnosis of GHD in adults may be established by GH provocative tests, provided that a reproducible test with clear normative limits is available. The insulin tolerance test (ITT) is a reliable diagnostic test in adults, but is contraindicated in several clinical conditions which are often observed in adult patients with suspected GHD. The other classic GH provocative tests, except the glucagon test, have a poor diagnostic utility and should be abandoned. GHRH combined with arginine or GH secretagogues represent a potent, safe, reproducible and reliable test which should be preferable to the ITT as a first-choice diagnostic test for GHD.