Introduction: Measurement of serum growth hormone (GH) concentration in
response to insulin-induced hypoglycaemia remains an important investigation in the
assessment of pituitary disease.
Methods In this audit, laboratories were presented with aliquots of sera
with GH concentrations likely to be found in an insulin stress test (IST). They were
invited to analyse the specimens for GH and comment on their results.
Results and discussion: A number of laboratories appeared to be using
out-of-consensus cut-off concentrations that sometimes were unrelated to the bias of
their GH assay. The specimens were chosen to mimic those seen in an IST that was
clearly not indicative of GH deficiency, so there was reasonable consensus in the
interpretation of results. However, five laboratories (9·6%) did indicate that their
results were equivocal.
