Methylmalonic acid (Urine) LC-MS/MS

Methylmalonic acid (MMA) is a compound produced during amino acid metabolism.
Increased production of MMA serves as a sensitive and early indicator of vitamin B12
deficiency.
Normally, vitamin B12 acts as a coenzyme, promoting the conversion of methylmalonyl
CoA to succinyl CoA. If there is not enough B12 available to act as a coenzyme,
then methylmalonyl CoA concentrations begin to rise, and the body converts the
methylmalonyl CoA to MMA instead. Decreased availability of B12 leads to increases
in blood and urine MMA levels.
Vitamin B12 deficiency can cause hematologic changes, such as anemia and large red
blood cells. It can also cause signs and symptoms of neuropathy, such as behavioral
changes (confusion, irritability, depression). Increased concentrations of MMA are often
detectible before the occurrence of hematologic changes.
Because a relatively large amount of the B12 found in the blood is bound to proteins
and is not freely available for analysis, MMA determination may be a better measure
of bioavailable B12 than the usual vitamin B12 tests. MMA and homocysteine (which
may be elevated when either B12 or folate are deficient) are valuable in detecting
early and mild cases of B12 deficiency