Methylmalonic Acid (MMA) Blood Test
Methylmalonic acid is a compound produced during amino acid metabolism that accumulates when vitamin B12 is insufficient. While a serum B12 test is the standard first step, it can miss early or mild deficiency. The MMA test detects deficiency at the cellular level and is often ordered alongside homocysteine when serum B12 falls in the lower half of the reference range. Together these markers provide the most reliable assessment of functional B12 status. Up to 20 % of the elderly may have insufficient B12, and vegetarians, vegans, pregnant women and those with gut conditions are at elevated risk.
Why Test Methylmalonate, MMA?
An MMA test is recommended when serum B12 is borderline or in the lower half of the reference range, especially if symptoms of B12 deficiency are present. It is also valuable as part of a comprehensive health check to uncover hidden deficiency early. Symptoms warranting testing include difficulty walking, mood swings, numbness, brain fog, fatigue, headaches, depression and anxiety.
What Do High Methylmalonate, MMA Levels Mean?
Elevated MMA combined with elevated homocysteine and mildly decreased serum B12 strongly suggests early or mild B12 deficiency, indicating a lack of B12 availability at the tissue level. If homocysteine is elevated but MMA is normal, a folate deficiency is more likely. Very high MMA in infants may indicate the rare inherited condition methylmalonic acidaemia. Kidney disease can also falsely elevate MMA.
What Do Low Methylmalonate, MMA Levels Mean?
Low MMA is the expected, healthy result and indicates that vitamin B12 is functioning adequately at the cellular level. It is not considered clinically significant.
Symptoms to Watch For
- Difficulty walking and balance problems
- Mood swings and irritability
- Numbness or tingling in hands and feet
- Brain fog and difficulty concentrating
- Persistent fatigue
- Headaches
- Depression and anxiety
- Anaemia symptoms (pale skin, weakness)
Who Should Get Tested?
- People with serum B12 in the lower half of the reference range
- Those with symptoms of B12 deficiency despite a normal serum test
- Vegans and vegetarians
- Elderly adults (50+)
- Pregnant or breastfeeding women
- People with malabsorption conditions or on stomach acid medication
How to Prepare for Your Test
No advance preparation or fasting is required. Bring valid ID to the lab.
Order Your Blood Test
Test your Methylmalonate, MMA levels with an accredited Swedish laboratory. Results within days, reviewed by Wellth.
Frequently Asked Questions
Why is MMA considered the gold standard for B12 testing?
Should I test MMA and B12 together?
Can kidney disease affect MMA results?
How does MMA differ from homocysteine as a B12 marker?
Reviewed by
Wellth Team
Wellth
Our content is written and reviewed by Wellth, and fact-checked against peer-reviewed research and current Swedish clinical guidelines.
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The information on this page is provided for informational purposes only and does not constitute professional medical advice, diagnosis, or treatment. Wellth provides health information and testing services but is not a substitute for clinical care. Always consult a qualified healthcare provider if you have questions about a medical condition. If you are experiencing severe or urgent symptoms, contact your doctor or call 1177 Vårdguiden. Blood test results should be interpreted by a qualified healthcare professional in the context of your complete medical history.