Methylmalonic Acid in Ruminant Urine — A Re-Evaluation

Colorimetric method for estimating methylmalonic acid in urine.

The increased urinary excretion of methylmalonic acid in vitamin B12 deficiency has attracted attention and several studies have suggested that it has clinical value as a test of vitamin B12 deficiency (Cox and White, 1962; Bashir, Hinterberger, and Jones, 1966). Chromatographic methods of estimation have been used but are either time consuming or only semiquantitative over a narrow range of me...

Gas-chromatographic determination of methylmalonic acid in urine and serum.

We describe a gas-chromatographic procedure for determining methylmalonic acid in serum and urine. The sample is acidified and the compound is extracted from it with diethyl ether, derivatized with N,Obis(trimethylsilyl)trifluoroacetamide, and gas chromatographed. Precision and sensitivity of the method were verified by recovery studies and by comparing the resultswith those foran established p...

The clinical evaluation of cobalamin deficiency by determination of methylmalonic acid in serum or urine is not invalidated by the presence of heterozygous methylmalonic-acidaemia.

It is well established that accumulation of methylmalonic acid may provide an early clue to the existence of tissue cobalamin (vitamin B12) deficiency. To verify whether methylmalonic acid accumulates in adult heterozygotes for inherited methylmalonic-acidaemia and thereby gives "false" positive test results for cobalamin deficiency, we measured the concentration of methylmalonic acid in serum ...

Cobalamin Deficiency During Pregnancy Expressed as Elevated Urine Methylmalonic Acid Levels Determined by a Photometric Assay

Aim: Deficiency of cobalamin and folate during pregnancy is associated with megaloblastic anemia. Lower levels of folate and vitamin B12 were reported in mothers whose offspring had neural tube defects compared to unaffected controls. Increased methylmalonic acid (MMA) levels are a sensitive indicator of mild vitamin B12 deficiency and elevated homocysteine levels denote vitamin B12 or folate d...

Urinary methylmalonic acid excretion.