MON-136 Reducing Unnecessary Inpatient Adrenocorticotropin Stimulation Tests

Background: Outpatient adrenocorticotropin (ACTH) stimulation tests can be challenging to interpret due to heterogeneously reported cut-offs. Inpatient stimulation tests present additional challenges due to the presence of acute illness and unreliable coordination of dynamic function testing on a busy inpatient service. This study aims to characterize the use of ACTH stimulation tests in hospitalized patients to determine necessity of testing. Methods: We conducted an inpatient audit of ACTH simulation tests done to rule out adrenal insufficiency between April 2018 to March 2019 at our institution. Normal post-ACTH response was defined as peak cortisol ≥500 nmol/L. Testing was considered inappropriate in patients with normal post-ACTH response who had a serum cortisol ≥250 nmol/L drawn during the same admission prior to stimulation testing. Cut-offs were based on previous analysis of 195 outpatient stimulation tests. Results: During the one-year study period there were 40 inpatients who had an ACTH stimulation test. Nineteen (48%) were considered unnecessary because patients either had a pre-ACTH serum cortisol ≥250 nmol/L and/or a 0-minute cortisol value just prior to the ACTH stimulation test ≥250 nmol/L. Except for a single instance where the patient was inappropriately on prednisone when basal cortisol was tested, all patients with any pre-ACTH cortisol ≥250 nmol/L had a normal post-ACTH response Conclusion: Institutions may avoid unnecessary inpatient ACTH stimulation tests by implementing protocols which ensure that basal cortisol levels are drawn and below locally determined cut-offs before proceeding to dynamic testing. To characterize further, a three-year analysis of inpatient ACTH stimulation tests is underway.