Vitamin B12

Cobalamin Test, Cyanocobalamin Test

What To Think About

• Vitamin B12 values that are slightly lower than normal (borderline) do not always mean that a person needs vitamin B12 injections. Borderline values should be evaluated with other tests.
• Folic acid levels can be high in people who lack vitamin B12. A folic acid test is often done at the same time as a vitamin B12 test. For more information, see the medical test Folic Acid.
• Methylmalonic acid is a substance in the blood that increases when vitamin B12 levels decrease. A methylmalonic acid (MMA) blood test may be done to help evaluate vitamin B12 test results.
• A change in homocysteine levels may also affect a change in vitamin B12 levels because of metabolism changes. For more information, see the medical test Homocysteine.

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Author:	Caroline Rea, RN, BS, MS	Last Updated: December 19, 2008
Medical Review:	Anne C. Poinier, MD - Internal Medicine Brian Leber, MDCM, FRCPC - Hematology
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