Good to knowOne result rarely tells the whole story. Your provider looks at your results together with your symptoms, exam, and other tests.
What the test is
Borderline results may be checked with a methylmalonic acid (MMA) test.
Why it's done
- Anemia with large red blood cells
- Numbness, tingling, balance problems, or memory changes
- Long-term metformin or acid-reducer use
- Vegan diet, weight-loss surgery, or gut conditions like celiac or Crohn's
Getting ready and what happens
- Your provider may ask you to fast for 6 to 8 hours.
- Tell your provider about B12 supplements or shots.
How the test is done
- A health worker cleans the skin, puts a band around your arm, and draws blood from a vein with a small needle. It takes a few minutes.
What the results mean
| Result | Typical range for adults |
|---|---|
| Vitamin B12 | About 200 to 900 pg/mL |
Normal ranges vary from lab to lab and can differ by age, sex, and pregnancy. Your report lists your lab's own range next to each result. A result a little outside the range is often not a problem.
Low (under about 200 pg/mL)
Suggests B12 deficiency. Causes include pernicious anemia, diet, gut absorption problems, and some medicines.
Borderline (about 200 to 300 pg/mL)
May still be low for your body. An MMA or homocysteine test can help decide.
High
Usually from supplements. Rarely linked with liver disease or some blood disorders.
Questions to ask your provider
- What do my results mean for me?
- Do I need to repeat this test or have other tests?
- Do I need B12 shots or will pills work?
- What's causing my low B12?
Risks
A blood draw is very safe. You may have slight pain or a small bruise where the needle went in.
Related conditions
Related medicines
Related tests
Sources
Last updated 2026-11-13.