What Is a Normal B12 Count?

Vitamin B-12, a nutrient found in animal products such as meat, seafood, poultry, eggs and dairy, plays a crucial role in metabolism, DNA synthesis and neurological function. Inadequate intake or absorption of vitamin B-12 can cause vitamin B-12 deficiency. If you have signs of this deficiency, you may need a blood test to determine B-12 levels in your blood.


Doctors typically draw blood to test vitamin B-12 levels. Patients should not eat or drink for about six to eight hours before the test, according to Medline Plus, a National Institutes of Health online medical encyclopedia. Certain medications may affect the test results, so discuss all medications you are taking with your doctor.

Normal B-12 Levels

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Doctors in the United States measure vitamin B-12 levels in picograms per milliliter, or pg/ml. Normal B-12 levels typically fall between 200 and 900 pg/ml, according to Medline Plus 1. Normal values may vary depending on the laboratory, however, so discuss your test results with your doctor.

Low Levels

Vitamin B-12 levels below 250 pg/ml may indicate a B-12 deficiency in adults, according to the National Institutes of Health Office of Dietary Supplements 2. Values below 170 pg/ml indicate a deficiency in most people, and values between 200 and 500 pg/ml may indicate a deficiency in older adults. Because excess vitamin B-12 leaves the body in urine, high levels of B-12 are rare, according to Medline Plus 1.

B-12 Deficiency Symptoms

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Common symptoms of vitamin B-12 deficiency include:

  • fatigue
  • weakness
  • shortness of breath
  • dizziness
  • difficulty concentrating
  • loss of appetite
  • weight loss
  • pale skin
  • sore or inflamed tongue

Prolonged vitamin B-12 deficiency may cause serious neurological symptoms, such as

  • confusion
  • memory loss
  • difficulty maintaining balance
  • depression
  • dementia