My Rheumy has instructed me to have a cortisol blood before I take a further reduction in Pred. At present on 8 mg. Has anyone had this test and if so how did you prepare for it, eg did you fast and did you take your daily dose of Pred? My surgery seem very vague about it. I also believe that you should rest for at least 30 mins before the blood is taken. Advice would be appreciated.