Dr. Klimas may already do these tests but the following were very helpful for me.
Ferritin level not just iron level. It can cause the same symptoms. Mine was so low and because I have RLS, and absoption problems from IBS, I had a nine hour infusion of iron which helped immensely. For RLS you need at least a reading of 120. I was 19 and it went up to 288. There's a wide range of what is normal, but depending on your health different ranges may be recommended for different health conditions.
B12 and Vitamin D as I was low in both so needed supplementation. You have to be careful with the vitamin D. Even though I was deficient, I started with a weekly megadose of D and developed a kidney stone which may have been related. I now take the daily dose.
Sleep study. I have sleep apnea as well as RLS and little deep stage sleep. I think everyone with our DD, should have this as most of us have some kind of sleep disorder.
These were definitely helpful for me. Dr. Klimas probably knows the above but a lot of doctors don't do these. tests.
As my neurologist said, while the above helped, I will always have the ME/CFS and fibromyalgia.
Barb C. :>)
While all these are now under control, it hasn't cured the CFS/ME but I do feel better.