What time is best to test cortisol for addisons? 6-8 30am?

Stimulation test: Cortisol is higher in the am than the pm, but it fluctuates all day long. If the degree of suspicious for addisons is low, a cortisol around 8 am plus electrolytes is probably fine. If the suspicion is high, you need to do an acth stimulation test. Baseline cortisol plus cortisol after injection of acth. This test can be done any time of day. See your endocrinologist.