Methylmalonic Acid Urine Test, GC/MS/MS

What is the purpose of this test?

Order this Methylmalonic Acid Urine Test, GC/MS/MS, which measures the level of MMA in urine to help detect early or mild vitamin B12 deficiency. Methylmalonic acid (MMA) is a substance produced in tiny amounts necessary for human metabolism and energy production. Vitamin B12 is responsible for two critical enzymatic reactions that promote cell metabolism. First, B12 promotes the conversion of methylmalonyl CoA (a form of MMA) to succinyl Coenzyme A, and with folic acid, aids in converting homocysteine to methionne. 

Urine levels of MMA rise when the B12 level begins to decrease; therefore, measuring elevated amounts of MMA in the urine is a sensitive and early indicator of vitamin B12 deficiency.

A B12 deficiency can occur due to malnutrition or gastrointestinal malabsorption issues. Over time, vitamin B12 deficiency can cause blood cell changes, leading to anemia and the production of large red blood cells. It can also cause signs and symptoms of neuropathy, such as numbness and tingling in the hands and feet, and, in advanced cases, mental or behavioral changes, such as cognitive impairment, confusion, irritability, and depression. An increased concentration of MMA is often detectable even before B12 levels abnormally decrease, the presence of blood cell changes, or before full-blown symptoms are apparent. However, some people may have some degree of neuropathy.

When should I order a Methylmalonic Acid Urine Test, GC/MS/MS?

Individuals may order this test if they have experienced symptoms related to vitamin B12 deficiency. Common signs or symptoms of vitamin B12 deficiency include:

• Diarrhea
• Dizziness
• Fatigue, muscle weakness
• Loss of appetite
• Pale skin
• Rapid heart rate, irregular heartbeats
• Shortness of breath
• Sore tongue and mouth
• Tingling, numbness, and burning in the feet, hands, arms, and legs
• Confusion or forgetfulness
• Paranoia