title: Insulin-like growth factor I levels and the diagnosis of adult growth hormone deficiency.
abstract: The current guidelines state that, within the appropriate clinical context, the diagnosis of adult growth hormone (GH) deficiency must be made biochemically using provocative tests. Measurement of insulin-like growth factor I (IGF-I) and binding protein 3 (IGFBP-3) levels cannot always distinguish between healthy and GH-deficient individuals. In particular, IGFBP-3 as a marker of GH status is clearly less sensitive than IGF-I and there is general agreement that its measurement does not provide useful diagnostic information. However, the diagnostic value of measuring IGF-I levels has been revisited recently. It has been confirmed that normal IGF-I levels do not rule out severe GH deficiency (GHD) in adults, in whom the diagnosis has therefore to be based on the demonstration of severe impairment of the peak GH response to provocative tests. It has also been emphasized that very low IGF-I levels in patients with high suspicion of GHD could be considered to be definite evidence for severe GHD. This assumption particularly applies to patients with childhood-onset, severe GHD or with multiple hypopituitary deficiencies acquired in adulthood. In addition, the use of IGF-I levels to monitor the efficacy and adequacy of recombinant human GH replacement remains widely accepted.
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Turin, Turin, Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Aimaretti
authors.forename: Ginevra
authors.initials: G
authors.lastname: Corneli
authors.forename: Silvia
authors.initials: S
authors.lastname: Rovere
authors.forename: Riccarda
authors.initials: R
authors.lastname: Granata
authors.forename: Roberto
authors.initials: R
authors.lastname: Baldelli
authors.forename: Silvia
authors.initials: S
authors.lastname: Grottoli
authors.forename: Ezio
authors.initials: E
authors.lastname: Ghigo
mesh_terms: D000328:Adult; D019382:Human Growth Hormone / Q000172:deficiency*; D006801:Humans; D007018:Hypopituitarism / Q000175:diagnosis; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000032:analysis*
chemical_list: D018972:Insulin-Like Growth Factor Binding Protein 3; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I