Hi Shannon,
I don't know how insurance works in your 'neck of the woods' but as it turned out (only in retrospect) your doctor was quite correct that your son didn't need an ACTH stimulation test because of his very high baseline levels. (Personally I think it is great to have one done so that you have all those figures at your fingertips as he grows older and neither of you can second guess the diagnosis or its severity).
In order to do an ACTH stim test now would require him to come off his medications for a short while and I don't think this is recommended in his case. Having said that, because he had such a high baseline level of 17-ohp (16,000+ ng/dL) he would probably only need to be off a couple of days to get a reasonably abnormal result, especially if you do it very soon before his levels have come right down.
Will your doctor write to your insurance company justifying his reasoning for NOT doing an ACTH stimulation test? Would that suffice?
