Critical evaluation of the 5-day metyrapone test

Different parameters of the response to the 5-day metyrapone test were evaluated for their diagnostic accuracy in tests given to 58 children and adolescents as part of an investigation for short stature. Insulin test, vasopressin test and ACTH test were used for diagnostic reference. A log transformation of the data was clearly appropriate. The maximal daily excretion of 17-ketogenic steroids was distinctly positively correlated with the basal excretion. Consequently, the most correct parameter of the response is the SD score of the deviation of the maximal excretion from the regression of the maximal excretion on the basal excretion in the reference population. This parameter, 'relative maximal excretion' was shown to be the diagnostically most accurate index of the response of 11 parameters studied.