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Vitamin B12 level

• Overview
• Risks
• Results

Normal Values:

Normal values are 200 - 900 pg/ml (picograms per milliliter).

What abnormal results mean:

Values of less than 100 pg/ml show a lack (deficiency) of vitamin B12. People with this deficiency are likely to have or develop symptoms.

Causes of vitamin B12 deficiency include:

• Not enough vitamin B12 in diet (rare except with a strict vegetarian diet)
• Poor absorption ( malabsorption ) diseases (for example, celiac disease and sprue)
• Lack of intrinsic factor
• Above normal heat production (hypermetabolic state - for example, with hyperthyroidism )
• Pregnancy

Increased vitamin B12 levels are uncommon. Usually excess vitamin B12 is removed in the urine. But disorders that affect the levels of vitamin B12 in the blood can lead to too much vitamin B12. These disorders include:

• Liver disease (such as cirrhosis or hepatitis )
• Myeloproliferative disorders (for example, myelocytic leukemia )

Other conditions under which the test may be done:

• Delirium
• Dementia
• Dementia due to metabolic causes

References:

Goldman L, Ausiello D. Cecil Textbook of Medicine . 22nd ed. Philadelphia, Pa: Saunders, 2003.

Hoffman R, Benz E, Shattil S, Furie B, Cohen H. Hematology: Basic Principles and Practice . 4th ed. Philadelphia, Pa: Churchill Livingstone, 2004.

• Review Date: 3/13/2007
• Reviewed By: Mark Levin, M.D., Hematologist and Oncologist, Newark, NJ. Review provided by VeriMed Healthcare Network.

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