Assessment of growth hormone status in acromegaly: what biochemical markers to measure and how?

Abstract

Various studies have evaluated the usefulness of measuring insulin-like growth factor I (IGF-I) and IGF-binding proteins, compared with growth hormone (GH), in the diagnosis and follow-up of patients with acromegaly. The clinical use of recently developed, highly sensitive GH assays has improved our understanding of the secretion of GH at very low concentrations. Studies examining the GH nadir after oral glucose administration in healthy adults suggest that GH values should be suppressed to no more than 0.14 microg/l after oral glucose administration. The highly sensitive GH assays are now being used in the diagnosis of patients with acromegaly and in post-treatment follow-up. In addition, the use of IGF-I immunoassays has confirmed that serum IGF-I level is a reliable and useful biochemical marker for determining GH excess. The widespread use of highly sensitive, carefully validated assays offers accurate and reproducible biochemical information that will help in the overall clinical management of patients with acromegaly, including the monitoring of disease remission, disease cure and treatment titration regimen, as well as the early recognition of patients with residual disease.