Might have figured out my problem. low acth <5 pg/ml but normal cortisol levels 15.6 pg/ml at 1030 am. doctor thinks addisons but how when cortisol is normal? cant get answer from doc at the moment! every other test was normal. thank you?

True Addison's disease would have elevated ACTH levels. A secondary adrenal insufficiency (pituitary problem) would cause a low ACTH. To diagnose, you would need an ACTH stimulation test. The other concerns would be any drugs/medications you are taking causing these levels or Non-ACTH Dependent Hypercortisolism, usually caused by a non-cancerous adrenal tumor.

Look at the normal values for your lab for time of day blood drawn. If one has adrenal Addison’s ACTH should be high and cortisol not High to low. Ifu have a pituitary problem causing Addison’s ACTH can be low. More common in women who have Sheehan’s syndrome. AKA pituitary apoplexy.