I think your son might be metabolizing the meds too rapidly. As you may know Cortef is short lasting; anywhere from 3 to 6 hours. You might want to talk to your endo about dividing the meds into smaller doses given 5 times a day. We dose at 3am, 7am, noon, 5pm and 10pm with the 3am and 7am being the largest doses and getting consecutively smaller through the day. This way it is never more than 5 hours between doses and helps even out the dips. When you have your son tested what time of day do you draw the blood and how soon is it after the last dose? This one shot test is only showing what your son’s levels are like at that moment and if it’s an hour after a dose it might be why the levels look good but there are obvious lows in the day. That is why the 24 hour urine profile might be good for him. This will show what’s going on for a whole day not just one minute in the day. Good luck. Julia