Methylmalonic Acid

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Also known as: MMA
Formal name: Methylmalonic Acid

The Test Sample

What is being tested?

Methylmalonic acid (MMA) is a compound produced in very small amounts during amino acid metabolism. Increased production of MMA occurs in vitamin B12 deficiency. This is because 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, methylmalonyl CoA concentrations begin to rise and the body converts the methylmalonyl CoA to MMA instead. Measurement of MMA in either urine or blood is therefore a sensitive marker of Vitamin B12 deficiency.

Increased production of MMA in newborn babies may suggest one of the inherited problems collectively called the methylmalonic acidaemias. Babies with this disease are unable to convert methylmalonyl CoA to succinyl CoA and therefore increased production of MMA is observed.

How is the sample collected for testing?

A blood sample is obtained by inserting a needle into a vein in your arm. A single random urine sample may be collected or a 24-hour collection of urine may be requested.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

You may be instructed to fast before sample collection for this test. Please follow any instructions that you are given.