A family member was off all supplements for about 10 days before testing levels. They found very high B12 & folate . We were told it meant a metabolic problem causing kidneys to have to hang on to all the B12 & folate they could because the CELLS still needed more.

DNA tests showed genetic variants hindering utilizaion of B12 and Folate (which would also mess up the whole mitochondrial energy production cycle using glycine etc).

The net of it is that in spite of the high blood levels, the family member is on Metanx (methylated B12, methylated folate and p-5-p).