Serum or plasma mass concentration of vitamin B12 (cobalamin)

Why This Test Might Be Ordered

Your doctor may recommend this test if you have symptoms like fatigue, numbness, tingling in the hands or feet, or trouble with balance and coordination. It may also be checked if you have a history of pernicious anemia, poor diet, or certain medical conditions like celiac disease or Crohn’s disease that can affect vitamin B12 absorption.

What to Expect Before the Test

No special preparation is needed for this test. You may have a blood draw at a clinic, doctor’s office, or lab. If you’re taking certain medications, like certain antibiotics or anti-anemia drugs, let your healthcare provider know before the test.

What the Results Mean

Low levels of vitamin B12 can indicate deficiencies that may require dietary changes, supplements, or medical treatment. High levels may be due to genetic conditions or other health issues and should be discussed with your doctor.

Common Causes of Abnormal Results

Low vitamin B12 levels can result from poor diet, malabsorption issues (like in pernicious anemia or Crohn’s disease), chronic kidney disease, or certain medications. High levels might be linked to genetic disorders or long-term vitamin B12 supplementation.