My friend has many symtoms of B12 deficiency. Fatigue, Dizzy, Numbness and tingling, shortness of breath, headaches, etc. Her B12 Blood Serum was 264 so her doctor did the MMA test. Her result was 20 which the results on her lab results said was normal (less than 40 is normal). So based on this, her doctor ruled out a B12 deficiency because the MMA was good. Wow. My friend has significant B12 deficiency symptoms and a low blood serum level but the MMA result convinced her physician that she does not have a B12 problem when it is clear from her symtpoms that she does. What do you make of this?