How should my vitamin B12 levels be measured?

You can get a blood test to measure your blood level of vitamin B12. However, such testing is generally not recommended unless you have symptoms of anemia or you have a disorder that prevents you from absorbing enough nutrients from food.

An adult whose B12 values fall below approximately 170-250 picograms/milliliter is considered vitamin B12 deficient.
Dr. David L. Katz, MD, MPH
Preventive Medicine
Preventive Medicine Specialist Dr. David Katz explains how a patient can get their vitamin B12 levels measured. Watch Dr. Katz's video for information on preventive medicine and overall wellness.
Many physicians think that to assess B12 one must measure B12 levels. However, it is well-established that B12 levels are not a sensitive marker for adequacy of B12 function. Some people suggest that measuring methylmalonic acid (MMA) is more sensitive. But at least one study shows that B12 function has a minimal effect on levels of MMA. Assessment of B12 status in practice involves measurement of a number of parameters, including the physical exam (depression, impaired balance, panic, neuropathy) the size of red blood cells (MCV), Hematocrit, homocysteine, and functional immunoassays.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.