MMA
The most sensitive marker of true B12 deficiency at the cellular level.
What is it
Methylmalonic acid accumulates when B12 is functionally insufficient. It is considered a more sensitive marker of true B12 deficiency than serum B12 alone in published research.
Why it's measured
Because serum B12 can be misleading at the borderline, MMA is used to confirm true cellular B12 deficiency.
Reference range
Standard laboratory reference
< 0.4 μmol/L
Reference ranges vary by laboratory. Your individual reference range will appear on your test report and should be interpreted by your physician in the context of your overall health profile.
What results may indicate
Elevated
Has been associated with functional B12 deficiency in research literature.
Lower
Is generally considered favorable.
These associations are general. They are not a personal diagnosis or prediction. Discuss your individual results with your physician in the context of your full health profile.
When it's measured
Used when B12 status is unclear or borderline.
Related markers
Measured in
A complete look at your heart, hormones, metabolism, inflammation, and longevity systems — drawn at Quest or LabCorp, reviewed by a U.S.-licensed physician.
Explore the Apex Panel →This information is for general educational purposes only and is not medical advice. Lab results alone are not intended to diagnose, treat, or cure any condition and do not replace the advice of a healthcare provider. OPTML does not offer medical advice, a diagnosis, medical treatment, or any form of medical opinion.