RESUMO
BACKGROUND: There are few data in the paediatric literature on the normal cortisol response to stimulation during the low dose synacthen test (LDST) (1 microg). AIM: To examine the cortisol responses in children, subsequently presumed to be normal, who had an LDST during anterior pituitary function tests (APFTs). METHODS: A retrospective review of results in children with short stature and normal growth hormone levels. RESULTS: Of 33 children tested, seven had suboptimal cortisol responses based on accepted criteria (peak <500 nmol/l)--a false positive rate of 21%. Only three of these children had a repeat LDST, which was normal in all cases. The peak cortisol response (median 633, range, 417-1052 nmol/l) was inversely correlated with age (r = -0.44, p < 0.05). CONCLUSION: One in five tests did not meet normal criteria. This false positive rate (21%) should be borne in mind when interpreting synacthen tests to prevent overdiagnosis of adrenal insufficiency.
