Serum Methylmalonic Acid (MMA)
Methylmalonic acid is the gold-standard functional biomarker for tissue-level vitamin B12 deficiency, reflecting intracellular enzymatic cofactor sufficiency.
Standard vs. Optimal Reference Rangesμmol/L
Standard reference intervals represent the statistical 95% distribution of unselected commercial populations. Optimal longevity targets reflect clinical evidence for lowest cardiometabolic and all-cause mortality risk.
Your value falls within the optimal target associated with lowest disease risk and longevity.
< 0.40 μmol/L
General reference distribution across unselected commercial populations.
< 0.20 μmol/L
Concentration target associated with minimal all-cause cardiometabolic mortality.
Molecular Mechanism & Clinical Purpose
Adenosylcobalamin is the obligate cofactor for methylmalonyl-CoA mutase, converting methylmalonyl-CoA to succinyl-CoA in mitochondria. In B12 deficiency, methylmalonyl-CoA hydrolyzes to MMA, spilling into circulation.
Differential Diagnosis
Elevated Levels (MMA High)
- •Intracellular vitamin B12 deficiency
- •Renal insufficiency (reduced urinary excretion of MMA)
Low Levels (MMA Low)
- •Optimal intracellular cobalamin status
Technical Reference & Deep Dive
Biochemistry & Enzymatic Pathways
Longevity Risk Architecture & Epidemiology
Pre-Analytical Caveats & Diagnostic Workup
Pre-Analytical Considerations:
Standard 10 to 12 hour overnight fast is recommended; avoid high-dose vitamin and mineral supplements for 24 hours prior to blood draw. Protect light-sensitive specimens (such as Vitamin B6, B12, and Folate) from ultraviolet light exposure by using amber collection tubes. Centrifuge and separate serum or plasma promptly to prevent in vitro leakage of intracellular minerals (e.g. magnesium, potassium) from red blood cells.
Reflexive Testing Protocol:
- Functional metabolic surrogate markers (Methylmalonic Acid for B12, Homocysteine for B6/B12/Folate, Red Blood Cell Magnesium)
- Complete Metabolic Panel and Ionized Calcium to evaluate electrolyte and mineral balance
- Celiac disease serology (Tissue Transglutaminase IgA with Total IgA) to screen for occult enteropathic malabsorption
- Parathyroid Hormone (PTH) and 24-Hour Urine Calcium quantification in cases of abnormal Vitamin D or calcium homeostasis
- Comprehensive Nutritional & Heavy Metal Trace Element panel via ICP-MS if multiple deficiencies are present
Clinical Citations & Primary Literature (1)
- [1]Methylmalonic Acid as a Biomarker of Vitamin B12 Deficiency and Longevity - Blood (2021). PMID: 33878260
Associated Longevity Guides & Clinical Calculators
Medicine 3.0Explore comprehensive evidence-based clinical protocols, testing costs, and algorithmic calculators that incorporate Serum Methylmalonic Acid (MMA) into overall healthspan optimization.