What should I do if my cortisol level is high on the 24 hour test?

Confirmatory test. The 24 urine test is a screening test, so it should pick up most people who truly have excess cortisol, but will also be falsely high in some normal people. To confirm excess cortisol production, a 2 day suppression test is done by having you take a pill called Dexamethasone for 2 days then having you get labs done.