Vitamin B12

Cobalamin Test, Cyanocobalamin Test

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include:

• Taking medicines, such as para-aminosalicylic acid, phenytoin (Dilantin), neomycin (Mycitracin), metformin (Glucophage), colchicine, omeprazole (Prilosec), lansoprazole (Prevacid), pantoprazole (Protonix), rabeprazole (such as Aciphex), methotrexate, triamterene, and birth control pills.
• Being pregnant or breast-feeding.
• Taking large doses of vitamin C.
• Drinking large amounts of alcohol.
• Having a test, such as a computed tomography (CT) scan, that used dyes in the past 7 days.
• Having pernicious anemia, which means you lack the substance (intrinsic factor) needed to absorb vitamin B12.

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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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