MMA Level Checker

MedlinePlus: “Normal values are 0.07 to 0.27 micromoles per liter.” NIH ODS: an MMA level “greater than 0.271 micromol/L suggests vitamin B12 deficiency”, and MMA levels “also rise with renal insufficiency and tend to be higher in older adults”. Labcorp prints a range of 0−378 nmol/L, and Mayo Clinic Laboratories “< or =0.40 nmol/mL”, the same number as 0.40 µmol/L.

How to use it

Find “Methylmalonic acid” (MMA) on your report, type the number and pick the unit beside it. µmol/L (also written micromol/L, umol/L or mcmol/L) and Mayo’s nmol/mL are the same number; nmol/L, the unit Labcorp prints, is 1,000 times bigger, and switching the unit converts what you typed. Then pick who the result is for. You see it against six lines from five sources, counted as the high lines it is over, with what those sources say about it. It does not diagnose anything: it places a number and quotes the sources.

What the test measures

MedlinePlus: “The methylmalonic acid blood test measures the amount of methylmalonic acid in the blood.” “This test may also be done with other tests to check for a vitamin B12 deficiency.” Cleveland Clinic on why it rises: “When you have low levels of B12 (also called cobalamin) or you aren’t absorbing B12 properly, your body makes more MMA.” NIH ODS: “Levels of serum methylmalonic acid (MMA), a vitamin B12-associated metabolite, are the most sensitive markers of vitamin B12 status, and an MMA level greater than 0.271 micromol/L suggests vitamin B12 deficiency”. Mayo Clinic Laboratories: “Several studies have suggested that the determination of serum or urinary methylmalonic acid could be a more reliable marker of vitamin B12 deficiency than direct vitamin B12 determination.”

The lines the sources print

Five sources, six lines, from 0.27 to 0.40 µmol/L. Labcorp: “A generally agreed on cutoff for elevated plasma MMA is 370 nmol/L.” Cleveland Clinic: “Normal blood (serum) MMA levels are usually under 0.40 µmol/L (micromole per liter, also written, umol/L or mcmol/L).” and “Normal blood and urine MMA levels can vary by lab.” Mayo Clinic Laboratories: “Intervals are Mayo-derived, unless otherwise designated.” MedlinePlus: “Normal value ranges may vary slightly among different labs. Some labs use different measurements or test different samples. Talk to your provider about the meaning of your specific test results.” The checker counts how many of the six a result is over. A result exactly on a line is read the way that source prints it: 0.27 is inside MedlinePlus’s range, 370 nmol/L is on Labcorp’s cutoff, 378 nmol/L inside its range, and 0.40 µmol/L inside Mayo’s line and on Cleveland Clinic’s.

Does MMA change with age?

None of these sources prints an MMA range by age: Mayo’s one line covers every age, and so do the others. What they say instead: NIH ODS, “However, MMA levels also rise with renal insufficiency and tend to be higher in older adults”; Labcorp, of its 370 nmol/L cutoff, “Approximately 2% of the US population and 7% of elderly persons have MMA concentrations above this threshold.”; Mayo Clinic Laboratories, “Diet, nutritional status, and age should be considered in the evaluation of serum or urine methylmalonic acid level.” Pick “An older adult” in the checker and those sentences sit beside the result.

A child’s result is another reading. Mayo Clinic Laboratories: “In pediatric patients, markedly elevated methylmalonic acid values indicate a probable diagnosis of methylmalonic acidemia. Additional confirmatory testing must be performed.” MedlinePlus: “If your baby has moderate or high levels of MMA, it may mean that they have methylmalonic acidemia.” A child’s or a baby’s result is read by their own doctor.

What the sources say a high or a low result can come from

MedlinePlus: “A higher than normal value may be due to vitamin B12 deficiency or methylmalonic acidemia.” and “The test can’t show how much of a deficiency.” Mayo Clinic Laboratories: “Other conditions such as kidney insufficiency, hypovolemia, and bacterial overgrowth of the small intestine also contribute to the possible causes of mild methylmalonic acidemia and aciduria.” On a low result, MedlinePlus: “Lower-than-normal levels of MMA are not common and are not considered a health problem.”

Read with B12 and homocysteine

NIH ODS: “Experts suggest that if a patient’s serum vitamin B12 level is between 150 to 399 pg/mL (111 to 294 pmol/L), the patient’s serum MMA levels should be checked to help confirm a diagnosis of vitamin B12 deficiency”. Cleveland Clinic: “If you have normal B12 levels and elevated MMA, you might still have a B12 deficiency — especially if you have symptoms.” and “Your provider will likely look at your MMA results along with the results of other tests, including B12 and homocysteine tests.” MedlinePlus: “To help make a diagnosis, your provider may compare your results with other tests including a homocysteine blood test and/or vitamin B tests.” Mayo Clinic Laboratories, on its homocysteine test: “Measurement of methylmalonic acid (MMA) distinguishes between vitamin B12 (cobalamin) and folate deficiencies, as MMA is only elevated in vitamin B12 deficiency.” The Vitamin B12 Level Checker places a B12 against ODS’s lines, and the Homocysteine Level Checker a homocysteine against Mayo’s range for your age and sex.

Before the blood draw

MedlinePlus: “No special preparation is necessary.” MedlinePlus again: “If you have questions about your results, talk to your provider. Your provider will consider your symptoms, medical history, and the results of other blood tests.”

Worked examples

• 0.32 µmol/L, an adult (the page’s example): over 2 of the 6 high lines — above MedlinePlus’s 0.27 and greater than ODS’s 0.271, yet under Labcorp’s 370 nmol/L cutoff and inside Mayo’s 0.40.
• 250 nmol/L: under all six high lines — 0.25 µmol/L, inside MedlinePlus’s normal values.
• 375 nmol/L: over 3 of the 6 — above MedlinePlus’s range, ODS’s line and Labcorp’s cutoff, and still inside Labcorp’s own 0–378 range.
• 0.40 µmol/L: over 4 of the 6 — inside Mayo’s “< or =0.40 nmol/mL” and on Cleveland Clinic’s 0.40.
• 0.05 µmol/L: below MedlinePlus’s normal values, and under every high line; MedlinePlus says lower-than-normal MMA is “not considered a health problem”.
• 0.5 µmol/L, an older adult: over all six high lines, with ODS’s and Labcorp’s sentences on older adults beside it.

Common mistakes

• Mixing µmol/L and nmol/L. 0.32 µmol/L is 320 nmol/L; typed in the wrong unit, a result moves 1,000 times. The checker asks when a number reads like the other unit.
• Reading one line as the only one. The six lines run from 0.27 to 0.40 µmol/L: 0.32 is over two of them and inside four.
• Reading MMA without B12. ODS sends B12 results between 150 and 399 pg/mL to an MMA test, and Cleveland Clinic reads the two together.
• Forgetting the kidneys and age. ODS: MMA levels “also rise with renal insufficiency and tend to be higher in older adults”.
• Reading a baby’s result like an adult’s. Mayo and MedlinePlus give a child’s or a baby’s high MMA its own meaning, and their own doctor reads it.

Frequently asked questions

More blood-test checkers: the Vitamin B12 Level Checker, the Homocysteine Level Checker, the Folate Level Checker and the MCV Level Checker. B12’s RDA for your age: the Vitamin & Mineral Dose Lookup.

Read next

• Vitamin B12 as a nootropic — the vitamin MMA is read with.
• Vitamin B9 — folate, the other half of the homocysteine story.
• Vitamin B6 as a nootropic
• Mind Lab Pro after 50 — B vitamins and age.

This is not medical advice, and nothing here diagnoses or treats anything. It shows where a number sits against published lines and quotes what the sources say about it; your lab’s own range, your vitamin B12, your kidneys, your age, what you take, your history and your doctor decide what it means. Some links on this site are affiliate links: I buy what I review at full price, and a commission never changes a verdict.