title: Diagnosis of growth-hormone deficiency in adults.
abstract: There is no consensus as to the most appropriate method of diagnosing growth-hormone (GH) deficiency in adults. We have evaluated the relative diagnostic merits of measuring peak GH response to insulin-induced hypoglycaemia (insulin tolerance test), mean 24 h GH concentration derived from 20 min sampling, serum insulin-like growth factor I (IGF-I) concentrations, and serum IGF binding protein 3 (IGFBP-3) concentrations. These tests were undertaken in 23 patients considered GH deficient from extensive organic pituitary disease, and in 35 sex-matched normal subjects of similar age and body-mass index. Hypopituitary subjects had significantly lower stimulated peak GH, mean 24 h GH, IGF-I, and IGFBP-3 concentrations than normal subjects. The ranges of stimulated peak GH responses were clearly separated between the hypopituitary (< 0.2-3.1 ng/mL) and normal (5.3-42.5 ng/mL) groups, but mean 24 h GH, IGF-I, and IGFBP-3 concentrations overlapped. Mean 24 h GH concentrations were below assay sensitivity in 80% of hypopituitary subjects and 16% of normal subjects. 70% and 72%, respectively, of the IGF-I and IGFBP-3 values in hypopituitary subjects were within the range for normal subjects. We conclude that GH deficiency in adults is most reliably identified by stimulatory testing, and that IGF-I and IGFBP-3 are poor diagnostic tests of adult GH deficiency.
authors.affiliation: Garvan Institute of Medical Research, St Vincent's Hospital, Sydney, NSW, Australia.
authors.forename: D M
authors.initials: DM
authors.lastname: Hoffman
authors.forename: A J
authors.initials: AJ
authors.lastname: O'Sullivan
authors.forename: R C
authors.initials: RC
authors.lastname: Baxter
authors.forename: K K
authors.initials: KK
authors.lastname: Ho
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015992:Body Mass Index; D002352:Carrier Proteins / Q000097:blood; D005260:Female; D005951:Glucose Tolerance Test; D006130:Growth Disorders / Q000175:diagnosis; D013006:Growth Hormone / Q000097:blood* / Q000172:deficiency*; D006801:Humans; D007018:Hypopituitarism / Q000097:blood*; D007328:Insulin / Q000008:administration & dosage; D018969:Insulin-Like Growth Factor Binding Proteins; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D008297:Male; D008875:Middle Aged; D011863:Radioimmunoassay; D012680:Sensitivity and Specificity
chemical_list: D002352:Carrier Proteins; D007328:Insulin; D018969:Insulin-Like Growth Factor Binding Proteins; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone