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Nutritional
Methylmalonic acid
Clinical biomarkerMetaboliteBlood/urinenmol/L
A functional marker that can rise with cellular vitamin B12 deficiency.
What it measures
Methylmalonic acid concentration.
Why it matters
Can help clarify B12 status when serum B12 is equivocal.
How to interpret it
Interpret with renal function and clinical context.
Important limitations
Kidney dysfunction can elevate MMA independently of B12 deficiency.
Evidence status
Clinical biomarker
Established context-specific functional biomarker.
Research & guidance
Original papers, validation studies, reviews and clinical guidance connected to this measurement.
For education and evidence exploration, not diagnosis or individualized medical advice.