Does subnormal reaction to ACTH stimulation definitely mean AI?

[Katbat45]

Hi there,

I recently had a 30 min synacthen test to investigate symptoms of muscle pain, weakness, fatigue, joint pain,  headaches and brain fog. My basal cortisol was 396 and 479 after 30mins.

I was unable to see my endo for the results as my daughter was in hospital at the time of our scheduled appointment, so I asked for the results to be sent to my own doc for the time being.  Endo described the results as 'subnormal' in his letter and that they 'may account' for my symptoms but I can't get an appointment to see the endo for another 5 weeks ..

Am wondering, do these results this mean I definitely have some kind of AI or could there be another explanation?

I'm  driving myself a bit crazy wondering if it's something serious or something that's easily treated without life long meds. Or even a false result? Have had symptoms for 2 years, getting steadily worse.

The numbers don't seem really super low, as in some people's cases. So I  wondered if there's some alternative reason cortisol might be low? .. Any help greatly appreciated.. Thanks