Doctor's Assessment Included
Every result includes a professional assessment from a BIG-registered doctor. For treatment decisions, discuss your results with your GP.
Methylmalonic Acid (MMA) (Blood)
MMA Blood measures functional B12 activity at the cellular level. For athletes, this test may detect subtle B12 insufficiency that could impair red blood cell production, oxygen transport, and muscle recovery before it shows on standard tests.
Reference Ranges
Low
0
Normal
0.4
High
Low
0
Normal
0.4
High
Reference ranges may vary between laboratories. When you order a test, a BIG-registered doctor assesses your personal results in context. For treatment decisions, discuss your results with your GP.
What It Measures
This test measures methylmalonic acid in your blood, a metabolite that accumulates when vitamin B12 is insufficient for normal metabolic reactions. MMA is considered a sensitive functional marker because it reflects actual B12 activity within your cells.
Why It Matters
Athletes with elevated MMA may experience reduced endurance and slower recovery due to functional B12 insufficiency. This test offers a deeper look at B12 metabolism than standard blood tests, potentially guiding targeted nutritional interventions for performance.
When to Test
Testing may be recommended when B12 deficiency is suspected but standard tests are inconclusive, when you have symptoms suggesting B12 deficiency with normal B12 levels, or to monitor the effectiveness of B12 treatment. Consult your healthcare provider.
Symptoms
Low Levels
Low MMA levels are generally considered normal and desirable, indicating adequate vitamin B12 function at the cellular level. This typically means your body has sufficient B12 to support its metabolic processes.
High Levels
Some people with elevated MMA levels may experience fatigue, weakness, tingling or numbness in extremities, cognitive difficulties, and balance problems. These symptoms may indicate functional B12 deficiency that should be evaluated by a healthcare provider.
Lifestyle Tips
If MMA levels are elevated, increasing B12 intake through diet or supplementation may be recommended by your healthcare provider. Regular monitoring can help track whether interventions are effectively lowering MMA back to normal levels.
Frequently Asked Questions
Why test MMA if I already tested B12?
MMA is a functional marker that reflects how B12 is being used at the cellular level. You can have seemingly normal B12 blood levels while still experiencing functional deficiency. MMA testing may reveal this hidden insufficiency.
Can kidney function affect MMA results?
Yes, reduced kidney function can cause MMA levels to rise independently of B12 status, since the kidneys are involved in clearing MMA from the blood. Your healthcare provider should consider kidney function when interpreting MMA results.
How quickly do MMA levels respond to B12 treatment?
MMA levels typically begin to decrease within days to weeks of adequate B12 supplementation. Your healthcare provider may recommend retesting after a period of treatment to confirm that levels are normalising.