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Vitamin B12 Blood Test

Sample Type:
Collection Method:Visit a Labcorp Location
HSA/FSA Accepted
No question this vitamin is crucial to your health, but are you getting enough of it?

You may think of it as just a vitamin you pass in the drugstore aisle, but B12 plays a supporting role in some of the body's most essential functions, from making red blood cells and DNA to supporting your nervous system.

This test measures the level of B12 (also called cobalamin) found in your blood. Lower than normal levels of B12 may cause fatigue, muscle weakness, intestinal problems, numbness, memory loss, anemia, as well as irreversible nerve damage if left untreated. Higher than normal levels of B12 may indicate a health condition, such as liver disease or diabetes.



No special preparation.

Why Consider This Test

Early Detection Matters

Early detection and treatment of B12 deficiency is important; if left untreated, it can cause severe neurologic problems and blood disorders.1

      Dietary Concerns

      All vitamin B12 comes from the foods you eat or vitamins and supplements you may take; you’re at risk of deficiency if you don’t get enough from your diet or aren’t able to absorb enough from the food you eat.2

        Icon Representation of Wellness
        At Greater Risk

        Those at greater risk for developing B12 deficiency are: 1,2,3,4,5

        • Individuals age 65 and older
        • Those with conditions that may affect the absorption of B12 in the body such as atrophic gastritis, which is a thinning of the lining of the stomach; pernicious anemia; and conditions such as celiac disease or Crohn’s disease
        • Individuals who have had surgery where part of the bowel that absorbs B12 was removed
        • People on the drug metformin for diabetes, or chloramphenicol, or those taking long-term antacid drugs, such as proton pump inhibitors or H2 blockers for heartburn
        • People following a strict vegetarian or vegan diet
        Warning Signs


        1. Skerrett, Patrick J. “Vitamin B12 Deficiency Can Be Sneaky, Harmful.” Harvard Health Blog, 11 Feb. 2019,
        2. “Vitamin B12.” NIH Office of Dietary Supplements, U.S. Department of Health and Human Services,
        3. Reinstatler, Lael, et al. “Association of Biochemical B12 Deficiency with Metformin Therapy and Vitamin B12 Supplements.” Diabetes Care, American Diabetes Association, 1 Feb. 2012,
        4. “Vitamin Deficiency Anemia.” Mayo Clinic, Mayo Foundation for Medical Education and Research, 9 Nov. 2016,
        5. Bermejo, Fernando, et al. “Should We Monitor Vitamin B12 and Folate Levels in Crohn's Disease Patients?” Scandinavian Journal of Gastroenterology, U.S. National Library of Medicine, Nov. 2013,

        How To Get This Test

        1. Choose Your Tests

        Shop for tests and pay online. An independent physician will review and approve your test requests; no doctor’s visit is required.


        2. Provide Your Sample

        Take the requisition number we emailed you, along with a photo ID, to a Labcorp location for sample collection.


        3. Access Your Results Online

        View your easy-to-read results online in your Labcorp OnDemand account. For certain results that require prompt attention, you will also be contacted by PWN health via phone or mail.


        Getting My Results

        We've made getting your results easier and more convenient than ever. View your easy-to-read results online in your Pixel by Labcorp account. For certain results that require prompt attention, you will also be contacted by phone or mail. To view a sample report click the "sample report" button below.

        View sample results

        Sample Report