A patient seated in the chair before a blood draw
In person

Vitamin B12

Your blood level of vitamin B12, from one standard blood draw.

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  • 2,000+ lab locations. Find one near you
  • Nothing due at the lab. FSA / HSA accepted
  • Ordered by a licensed clinician

At a glance

Collection
Blood draw
A standard blood draw at the lab.
Preparation
None
Nothing to do ahead of time. Water is fine.
Results
1 to 3 days
Typical turnaround after your visit.
Where
2,000+ lab locations
Nationwide, with nothing due at the lab.

About this test

Vitamin B12 is a vitamin your body needs to make red blood cells and keep nerves working. It comes from food, mostly animal products, and is absorbed with help from the stomach. Low levels can be linked to diet or to absorption problems, so B12 is often checked with folate.

For adults 18 and older. Test availability varies by lab location.

Who should take this test?

This test is often used by adults with tiredness, tingling or numbness, a plant-based diet, or past stomach surgery that can affect absorption. Commonly related symptoms include:

Body

  • Tiredness
  • Weakness
  • Tingling in hands or feet

Skin

  • Pale skin

Mood

  • Trouble concentrating
  • Memory changes

Lifestyle

  • Plant-based diet

Ask about this test

Not sure this is the right test?

AI-generated. For information only, not medical advice. Call 911 for an emergency.

What does this test measure?

Your result shows how much B12 is in your blood, which a healthcare provider can read with folate, a blood count, and your symptoms to understand what may be going on.

Vitamin B12
Vitamin B12 helps your body make red blood cells and keeps nerves working well. It comes from animal foods and fortified foods, and it needs a healthy stomach and gut to be absorbed. Levels can be lower with plant-based diets, some medicines, and conditions that affect absorption.
Why it’s measured: A vitamin your body needs to make red blood cells and keep nerves healthy.

How it works

  1. Step 1

    Order online

    Check out here. A licensed clinician in your state reviews your order and sends it to the lab.

  2. Step 2

    Visit a lab

    Bring a photo ID to any of 2,000+ lab locations. No fasting needed, and nothing is due at the lab.

  3. Step 3

    Get your results

    Results post to your account, usually in 1 to 3 days, each number next to the lab’s reference range.

Find a lab near you

Choose from 2,000+ lab locations nationwide. Your order works at any of them.

What your results tell you

B12 is reported as a number and compared with the lab’s reference range. A result near the low end may be read with other tests.

  • Your number next to the lab’s reference range
  • Explained in plain language
  • A licensed clinician reviews your order and, if appropriate, orders the test.
  • A lab report you can download and share

A healthcare provider reads B12 with folate and other results, looks for a cause of any low level, and decides on next steps.

Clinical-grade testing, from the comfort of home.

From the lab to your report, every step of our process meets the gold standard in medical testing.

  • CLIA-certified labs

    Every lab we partner with is certified under the Clinical Laboratory Improvement Amendments, meeting both state and federal standards with regular independent inspections.

  • We protect your health data

    We protect your health data with encryption and do not sell it. Some results must be reported to public health authorities by law. See our Privacy Notice.

  • Rigorous quality assurance

    All partner labs run regular internal quality checks, participate in proficiency testing, and comply with federal and state lab regulations.

  • Clinician-reviewed reports

    Results are reviewed by an independent, licensed clinician.

Questions

Common questions.

Anything else, our care team answers by phone, text, or email.

B12 comes mostly from animal foods, so people who eat few or no animal products can have lower levels. Low B12 can also come from trouble absorbing it, such as after stomach surgery, with some digestive conditions, or with pernicious anemia, a condition where the body cannot absorb B12 well.

A healthcare provider can help find the cause.

B12 and folate work together to make red blood cells, and low levels of either can lead to a similar kind of anemia. Low B12 can also make it harder for cells to use folate. Checking both helps a healthcare provider see which one may be behind a result.

A blood B12 level is a useful first check, but it may not match what is happening in your cells, especially when a result is near the low end. A healthcare provider may add other tests in that case.

B12 also cannot explain tiredness on its own. If you take B12 or a multivitamin, tell your healthcare provider, since it can raise your result. Don’t stop or change any medicine or supplement without talking with your healthcare provider.

Lab tests are informational and don’t diagnose conditions on their own. Available to adults 18 and older; test availability varies by lab location. A licensed clinician reviews your order and, if appropriate, orders the test. All testing is performed at CLIA-certified laboratories. Not for emergencies: if you think you may be having a medical emergency, call 911.