Comparison of the adrenocorticotropic hormone stimulation test with and without prior dexamethasone suppression in the diagnosis of congenital adrenal hyperplasia

: A comparison was made of the ACTH stimulation test with and without prior dexamethasone suppression in 10 patients, each of whom served as her own control. It was found that it is not necessary to administer DEX before the test, the specificity and sensitivity of both tests being the same in the diagnosis of CAH, although the calculated values are lower when DEX is given. Further investigation with HLA typing and ACTH stimulation testing is necessary to establish whether either or both types of ACTH stimulation tests are capable of discriminating between the heterozygotic and homozygotic varieties of CAH.