title: Diagnosis of acromegaly: state of the art.
abstract: BACKGROUND
  Biochemical diagnosis of acromegaly relies on measurement of insulin-like growth factor-1 (IGF-1) and growth hormone (GH). An elevated IGF-1 level above the age- and gender-specific normal range and nonsuppression of GH to oral glucose load to a nadir < 0.4 ng/ml in sensitive assays are currently considered diagnostic of acromegaly. Lack of normative data for both IGF-1 and GH across a wide range of populations and ethnicities, interassay and intraassay laboratory variability, pulsatility of GH secretion, and effects of medications and hormones may confound interpretation of these biochemical tests.
  
  
  METHODS
  Clinical situations in which acromegaly should be suspected and/or investigated. Strengths and limitations of current IGF-1/GH assays are discussed. Clinical scenarios with discordant GH suppression test and IGF-1 levels and, briefly, acromegaly in pregnancy, prolactin-cosecreting tumors, familial acromegaly, and nonpituitary acromegaly are also discussed.
  
  
  CONCLUSIONS
  Serum IGF-1 is the cornerstone and in most cases the stand-alone test in the diagnosis and follow-up in patients with acromegaly. Diagnosis depends on the accurate and reliable measurement of serum IGF-1. GH suppression testing is currently used in limited clinical setting. Standardization of IGF-1 assay and development of normative data across a wide population base are needed. Newer bioassays for IGF-1 hold promise for future.
authors: Endocrinology and Metabolism Institute, Cleveland Clinic Foundation, 9500 Euclid Avenue, Desk F20, Cleveland, OH 44195, USA.
authors: Subramanian
authors: S
authors: Kannan
authors: Laurence
authors: L
authors: Kennedy
mesh_terms: D000172:Acromegaly / Q000097:blood / Q000175:diagnosis*; D019382:Human Growth Hormone / Q000097:blood; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008279:Magnetic Resonance Imaging; D011788:Quality of Life; D011795:Surveys and Questionnaires
chemical_list: D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I