From own experience of endocrinologists thou they specialise in hormones, have been fairy poor just due to their lack of knowledge of ME/CFS and hence usually not really interested in giving us much in the way of tests which would be useful to most who have this.
Many naturopaths seem to be more of a help.
Yes the ME abnormalities are in tests they usually dont tend to think on doing on us eg free testosterone is one I can think of, testing cortisol levels at different times is another (they tend to just do simple morning cortisol test. Many have better cortisol tests done throu naturopaths).
I suggest to find a doctor who has an interest in CFS and in hormones to probably really make it worth while