Vitamin B12
Measures vitamin B12 levels to detect deficiency that can cause anemia, nerve problems, and fatigue.
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What this test measures
This test measures the amount of vitamin B12, also known as cobalamin, in the blood. Vitamin B12 is vital for good health as it helps the body make red blood cells, maintain nervous system function, and create DNA. This water-soluble vitamin is primarily found in animal products such as red meat, dairy, and eggs, and requires intrinsic factor produced by the stomach for proper absorption.
Vitamin B12 plays several critical roles in maintaining health. Once absorbed, B12 serves as a cofactor for enzymes involved in DNA synthesis, fatty acid production, and myelin formation. The vitamin is also essential for the enzyme methylmalonyl-CoA mutase, which converts methylmalonyl-CoA to succinyl-CoA, and when deficient, methylmalonic acid levels accumulate in the blood. Testing vitamin B12 levels can help identify deficiencies that may cause serious health problems if left untreated.
Who should consider this test
You might consider this test if you are experiencing any of the following:
- Individuals following vegetarian or vegan diets, as B12 is primarily found in animal products
- Adults over 60 years old, who may have reduced ability to absorb vitamin B12 from food
- Those with digestive disorders such as Crohn's disease, celiac disease, or pernicious anemia that affect nutrient absorption
- People experiencing symptoms like fatigue, weakness, pale skin, numbness in hands or feet, or memory problems
- Individuals who have had gastric surgery or take medications that reduce stomach acid production
- Those with a family history of pernicious anemia or autoimmune conditions
What to expect
Preparation
Fasting for 6-8 hours before the test may be recommended by some providers, though it is not always required. Individuals should inform their healthcare provider about any medications or vitamin B12 supplements they are taking, as these may affect test results.
Sample Type
A standard blood sample drawn from a vein, typically from the arm.
Collection
A healthcare professional will insert a needle into a vein and collect blood in an air-tight vial or syringe. The procedure is quick and involves minimal discomfort.
Turnaround
Results are typically available within 1-3 business days after the laboratory receives the sample.
Understanding your results
Vitamin B12 test results are reported in picograms per milliliter (pg/mL) or picomoles per liter (pmol/L). Results help healthcare providers determine whether an individual has adequate vitamin B12 levels or may be experiencing deficiency. The normal range can vary slightly depending on the laboratory, with typical normal levels ranging from 160-950 pg/mL.
| Population | Reference Range | Notes |
|---|---|---|
| Adults | 160-950 pg/mL (118-701 pmol/L) | General reference range; some laboratories may use slightly different ranges |
| Borderline | 200-300 pg/mL (148-221 pmol/L) | May require additional testing or monitoring |
Reference ranges shown are general guidelines. Your lab report will include the specific reference range used by the laboratory that processed your sample, which is the authoritative range for interpreting your results.
What does a “Low” result mean?
Levels below 160 pg/mL (118 pmol/L) may indicate vitamin B12 deficiency, and individuals with this degree of deficiency are likely to have or develop symptoms. Results between 200-300 pg/mL are considered borderline and may require additional testing. Low B12 levels may suggest vitamin B12 deficiency, pernicious anemia, or an overactive thyroid. Deficiency should often be confirmed by checking methylmalonic acid levels, as elevated MMA indicates true B12 deficiency.
What does a “High” result mean?
Increased vitamin B12 levels are uncommon, as excess vitamin B12 is typically removed through urine. Abnormally high levels (over 900 pg/mL) may suggest underlying conditions such as liver disease, kidney problems, diabetes, or certain forms of leukemia. While elevated B12 levels are generally rare and usually not concerning, extremely high levels warrant evaluation by a healthcare provider to assess for underlying conditions.
Privacy & confidentiality
All test orders are authorized and results reviewed by an independent, board-certified physician who is not the patient's personal doctor. Your vitamin B12 test results are completely confidential and handled with the utmost privacy. Results are <u>not reported to your doctor</u> unless you choose to share them, and they are <u>not part of your medical records</u> maintained by your healthcare provider. The test results will <u>not appear on insurance statements</u> or explanation of benefits (EOB) forms, ensuring your privacy is fully protected. We understand that some individuals prefer to monitor their health markers privately before discussing them with their healthcare provider. Your test information is never shared with employers, insurance companies, or government agencies. All results are delivered securely through your confidential online portal, accessible only with your login credentials. This private testing approach allows individuals to take control of their health monitoring with complete discretion and peace of mind.
Frequently asked questions
Related tests
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$49Often tested together with B12 as both vitamins are involved in similar metabolic processes and deficiencies can cause similar types of anemia
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View TestComprehensive Metabolic Panel (CMP)
$29Provides additional information about liver and kidney function, which can be affected by or contribute to vitamin B12 abnormalities
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CPT Code: 82607
This test may not be available in: NY, NJ, RI
This page is for informational purposes only and does not constitute medical advice. Always consult with a healthcare provider regarding any health concerns. LevelPanel does not diagnose, treat, or prescribe.
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