Dx with adrenal insufficiency, before acth test could be done, sent to ER was given IV steroids. Doc does blood work often looking at cortisol levels, but should she still do the acth test?

ACTH test. In addition to doing the acth test and seeing an endocrinologist, it would be important to know why you developed addisons. Autoimmune adrenal? Adrenal hemmorhage? Pituitary?
Yes. Adrenal stimulation test still can be done, but it depends upon whether you're receiving corticosteroids that can be picked up in the blood test. Talk w/an endocrinologist.
ACTH is made in the. Pituitary, and is suppressed if you are taking glucocorticoids., and cortisol is one. Your doctorprobably is managing your cortisol lack symtomatically, and should urge extra dose Prednisone or Dexamethasone if you are stressed. Please discuss why with you endocrinologist.