Methylmalonic Acid (MMA) Test
The MMA test measures the level of methylmalonic acid in your blood or urine to help diagnose vitamin B12 deficiency and certain rare genetic disorders.
What is a methylmalonic acid (MMA) test?
This test measures the amount of methylmalonic acid (MMA) in your blood or urine. MMA is a substance produced during the digestion of protein. Vitamin B12 is required to break down MMA; therefore, high levels of MMA can indicate a vitamin B12 deficiency. Vitamin B12 is essential for metabolism and the production of red blood cells.
Why do I need an MMA test?
You may need this test if you exhibit symptoms of a vitamin B12 deficiency, which include:
- Fatigue and dizziness
- Shortness of breath
- Tingling in hands and/or feet
- Mood changes, confusion, or irritability
- Loss of appetite
- Pale skin
You may be at higher risk for deficiency if you are a strict vegetarian or vegan, have digestive diseases like celiac or Crohn's disease, have an alcohol use disorder, or are older than 75 years.
What happens during an MMA test?
MMA levels can be checked via a blood sample or a urine sample. For a blood test, a professional collects a small amount of blood from a vein in your arm. For urine testing, you may be asked to provide a random sample or a 24-hour collection, where you store all urine produced over a 24-hour period in a special container.
What do the results mean?
Higher-than-normal levels of MMA may indicate a vitamin B12 deficiency. Your provider will likely compare these results with other tests, such as a homocysteine blood test, to confirm a diagnosis. In newborns, high levels of MMA may indicate methylmalonic acidemia, a rare genetic disorder that requires prompt medical attention.