Methylmalonic Acid MMA Serum Levels

Serum methylmalonic acid (MMA) measurement is used to evaluate individuals with signs and symptoms associated with vitamin B₁₂ deficiency or congenital methylmalonic academia.

MMA is Vitamin B12 dependent byproduct of amino acid breakdown. Vitamin B₁₂ deficiency causes an accumulation of MMA in the serum. MMA concentrations will often become elevated in the early stages of vitamin B₁₂ deficiency even while serum levels of B12 appear normal.  Consequently, It may be used as a diagnostic test for B12 deficiency in assessing the effectiveness of vitamin B₁₂ supplementation of deficient patients.

Vitamin B₁₂ deficiency causes macrocytic anemias and decreased erythrocyte survival due to abnormal maturation of erythrocyte precursors in the bone marrow. Pernicious anemia is a form of vitamin B₁₂ deficiency that is caused by a lack of intrinsic factor.

Low vitamin B₁₂ intake, gastrectomy, malabsorption, and transcobalamin deficiency can also cause vitamin B₁₂ deficiency.

A generally agreed on cutoff for elevated plasma MMA is 370 nmol/L.