A brief review of the use and utility of growth hormone stimulation testing in the NCGS: do we need to do provocative GH testing?

True growth hormone deficiency (GHD) in childhood, while rare, has major clinical consequences. GHD is often associated with other pituitary hormone deficiencies, so these children may require multiple hormonal replacement and close clinical follow-up to optimize their outcome. Growth hormone stimulation testing (GHST), as currently conducted, is not a reliable diagnostic tool. Both changes in growth hormone assay methodologies and increases in the diagnostic threshold contribute to the incorrect labeling of a substantial proportion of normal children as having idiopathic GHD. Fortunately, newer imaging technologies and laboratory tests form a more rational basis to diagnose true GHD. The use of GHST among GH-naive subjects (<20 years of age) enrolled in the National Cooperative Growth Study has declined over the past two decades, from a high of 89% between 1987 and 1989 to only 52% in 2002. Given that GH stimulation testing does not meaningfully aid in distinguishing those few children with true growth hormone deficiency from the much more common short normal child and that alternatives are now available, it is time to discontinue the routine use of GHST in children.