Why does the blood draw have to be in the morning?

ACTH levels change through the day. Quest requires collection between 7 a.m. and 10 a.m. so the listed reference ranges apply.

Is ACTH tested with cortisol?

Yes. Providers usually compare ACTH and cortisol together to find the source of a problem.

Quest specifies plasma collected in an EDTA (lavender-top) tube.

Yes, including steroid medicines. Tell your provider what you take, and do not stop anything without guidance.

Hormone and endocrine health

A plasma test that measures adrenocorticotropic hormone, a pituitary hormone that signals the adrenal glands to make cortisol.