Is it possible to have a vitamin b12 deficiency if your serum level is 250 p/mol? have every symptom plus high mcv and mch

As a matter of fact yes: I cannot go into the complex details, but I had two young patient's years ago, both of whom had elevated blood levels of vitamin B12. But both of them also had evidence of thiamin deficiency that would result in deficiency of energy. I concluded that vitamin B12 was collecting in the blood and not being used in metabolism. Try a supplement of thiamin and see whether the vitamin B12 levels come down.