B12 is an important vitamin that is involved in metabolism, red blood cell formation and central nervous system function. Vitamin B12 is found in milk products, shellfish, poultry, eggs and meat. A vitamin B12 level is generally drawn to diagnose or monitor conditions such as pernicious anemia, symptoms of an abnormal B12 level, delirium and dementia.
The Test
A blood test for a vitamin B12 level is obtained from a vein in your arm or hand. You should not eat or drink for at least six hours before this test or as advised by your physician.
Normal Level
According to MedlinePlus.com, a normal level of vitamin B12 is between 200 to 900 picograms per milliliter. Your physician will determine if your vitamin B12 level is abnormal since normal levels differ slightly from laboratory to laboratory.
Decreased Levels
Decreased vitamin B12 levels indicate lack of the intrinsic factor which is necessary for vitamin B12 absorption, insufficient vitamin B12 in your diet, celiac disease, Crohn's disease, hyperthyroidism, pregnancy and pernicious anemia.
Increased Levels
Increased vitamin B12 levels may signify leukemia, polycythemia vera and liver disease, such as cirrhosis and hepatitis.
Medication Interactions
Chloral hydrate is a medication that may increase vitamin B12 levels. Certain medications that may decrease vitamin B12 levels include alcohol, aspirin, aminoglycosides, anti-convulants, colchicine and oral contraceptives.
References
- MedlinePlus: Vitamin B12 Level
- MedlinePlus: Vitamin B12
- Mosby's Diagnostic and Laboratory Test Reference: Ninth Edition; Kathleen Deska Pagana PhD RN & Timothy J. Pagana MD FACS; October 17, 2008
