Role of sampling times and serum cortisol cut-off concentrations on the routine assessment of adrenal function using the standard cosyntropin test in an academic hospital from Spain: a retrospective chart review.

Abstract

Aiming to validate the use of a single poststimulus sampling protocol for cosyntropin test short standard high-dose test (SST) in our institution, our primary objectives were (1) to determine the concordance between 30 and 60 min serum cortisol (SC) measurements during SST; and (2) to evaluate the diagnostic agreement between both sampling times when using classic or assay-specific and sex-specific SC cut-off values. The secondary objectives included (1) estimating the specificity and positive predictive value of 30 and 60 min sampling times while considering the suspected origin of adrenal insufficiency (AI); and (2) obtaining assay-specific cut-off values for SC after SST in a group of subjects with normal hypothalamic-pituitary-adrenal (HPA) axis.