I am in an extended crash approaching whitney level of illness. And I also already have doctors that are better than 90 percent of the ones ppl have z they know what me/cfs is and mcas and pots and eds and dont force exercise on me. but I know that's not good enough. IRS not simple for me to get a doctor though. A really good doctor who is me/cfs specialist and advocates for me is a rare privilege I currently dont have. I'm trying my best.Maybe you should find a different doctor. MMA is far superior to serum B12, which misses many B12 deficiencies.
In the meantime, on a CBC, if MCV is over 94 or so, you might suspect B12 deficiency, although it could also be folate or B6.
Cbcs normal except eosinophils high I think but that's been true for years