I am asking for a friend. Her "diagnosis" is CFS. She is not taking any supplements at all. Lives in Canada, where food is fortified with Folic Acid. RBC Folate 2283 B12 231 MTHFR C677T/A1298C +/+ Compound heterozygous MTRR A664A +/+ MTRR A66G +/- COMT +/- x 2 Definitely B12 deficient. But is the RBC Folate high because of the MTHFR or because there is not enough B12 there to utilize the folate? Or a bit of both !!