Lab test
Vitamin B12 Deficiency Test
This blood test evaluates vitamin B12 levels and can determine whether a deficiency is present.
- Typical price
- From $35
- Results
- 1-3 business days
- Preparation
- See preparation notes below
- Sample
- Blood draw or sample collection at a local center
About this test
This blood test evaluates vitamin B12 levels and can determine whether a deficiency is present. Vitamin B12 is needed for normal red blood cell production and nerve function. Deficiency can develop from a diet low in animal products, from digestive disorders that impair absorption, or from certain medicines, and it may cause fatigue, tingling, or a type of anemia. The test is often ordered when a blood count is abnormal or when symptoms suggest low B12. It may be measured with folate and other tests for a complete picture.
What this test measures
- Vitamin B12 Measures the level of this B vitamin in the blood.
- Folic acid (folate) Often measured alongside B12 because the two interact.
- Methylmalonic acid (MMA) Sometimes added to help confirm a borderline B12 deficiency.
Who this test may be right for
- People with fatigue, weakness, or tingling in the hands or feet
- Individuals with anemia or unusually large red blood cells
- People following vegan or vegetarian diets
- Those with digestive conditions that impair absorption
- People taking medicines that affect B12 levels
Before your visit
- Fasting may be requested for some panels.
- Tell the collector about vitamin B12 supplements you take.
- Follow any instructions provided for your specific panel.
Understanding your results
A low vitamin B12 level suggests deficiency, which can explain certain types of anemia and nerve symptoms. A high level is usually related to supplements. Borderline results sometimes prompt an additional marker such as methylmalonic acid to confirm the finding. Discuss results with a healthcare provider, who can determine the cause and next steps.
Order this test online
- Buy online in a few minutes - no doctor's visit needed for most tests.
- Sample collection at a patient service center near you.
- Results are typically ready within 1-3 business days.
- Secure, lab-reviewed results delivered to your account.
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Questions people ask
Can vitamin B12 deficiency cause symptoms before anemia appears?
Yes. Tingling, balance problems, and fatigue can occur before blood counts change, which is why B12 may be tested when these symptoms are present.
Why might a vegan or vegetarian diet lead to low vitamin B12?
Vitamin B12 occurs naturally mainly in animal products, so people who avoid them may have lower intake unless fortified foods or supplements are used.
What if my vitamin B12 result is borderline?
A borderline level may be followed up with another marker, such as methylmalonic acid, to help confirm whether deficiency is present. A provider decides if this is needed.
Do supplements affect a vitamin B12 result?
Yes. Recent B12 supplements can raise measured levels, so tell the collector what you take and follow any preparation instructions.
What does the Vitamin B12 Deficiency Test measure?
This blood test is used to evaluate Vitamin B12 levels and can determine if there is a vitamin B12 deficiency.
Do I need to fast before this test?
Follow the lab's instructions.
How long do results take?
Most Vitamin B12 Deficiency Test results are released in 1-3 business days. Specialty testing can take longer.
Is this test right for me?
This page is educational and not medical advice. Talk to a licensed healthcare provider about which tests fit your situation.
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