Specimen requirements- 0.5 ml non-hemolyzed serum, fasting preferred
Serum should remain frozen during shipment to lab
Reference intervals:
Dogs: 415−1,193 nmol/L
Cats: 139−897 nmol/L
Serum Methylmalonic acid (MMA) can be used as a marker for cobalamin deficiency on a cellular level and is often measured in combination with cobalamin (vitamin B12). Cobalamin is an essential cofactor for the enzyme methylmalonyl CoA mutase, which converts L-methylmalonyl CoA to succinyl CoA. When dogs or cats are cobalamin deficient the physiologic metabolic pathway is reversed and the production of MMA is favored. MMA can diagnose cobalamin deficiency in patients that have a low normal serum cobalamin concentration. Cellular cobalamin concentrations are more important than serum cobalamin concentrations because cobalamin-dependent biochemical reactions occur intracellularly. Since MMA is renally excreted, increased concentrations should be interpreted cautiously in patients with renal failure.
References
1.Ruaux CG, Steiner JM, Williams DA. Metabolism of amino acids in cats with severe cobalamin deficiency. Am J Vet Res2001;62:1852-1858.
2. Stabler SP, Marcell PD, Podell ER, Allen RH, Lindenbaum J. Assay of methylmalonic acid in the serum of patients with cobalamin deficiency using capillary gas chromatography-mass spectrometry. J Clin Invest 1986;77:1606-1612.
3. Ruaux CG, Steiner JM, Williams DA. Relationships between low serum cobalaminconcentrations and methylmalonic acidemia in cats. J Vet Intern Med 2009;23:472-475.
4.Berghoff N, Suchodolski JS, Steiner JM. Association between serum cobalamin and methylmalonic acid concentrations in dogs. Vet J 2012;191:306–311.
5. Berghoff N, Parnell NK, Hill S, Suchodolski JS, Steiner JM. Serum cobalamin and methylmalonic acid concentrations in dogs with chronic gastrointestinal disease. Am J Vet Res 2013;74:84-89.
