Shanti then told me something I didn't know. Miss A's blood results over the last few years showed her MMA levels were always elevated even if her B12 levels were within the normal range. My results and Miss L's were the same. Even after B12 injections the B12 levels increased but the MMA stayed high.
MMA explanation: http://www.mayomedicallaboratories.com/test-catalog/Clinical+and+Interpretive/80289