Vitamin B12 is needed to make red blood cells, DNA and to keep nerves healthy. It is found almost only in animal foods.
- Normal range (adults)
- 200–900 pg/mL (148–664 pmol/L)
- Sample
- Blood
- Fasting
- Not usually needed
- Also called
- Vit B12, B12, Cobalamin, Cyanocobalamin, Serum B12, Serum Cobalamin
Vitamin B12 normal range
| Group | pg/mLConventional units: US, South Asia | pmol/LSI units: UK, Europe, Australia, international |
|---|---|---|
| Adults | 200–900 | 148–664 |
Your report may use either unit system; labs in the Gulf often print both. Ranges also vary slightly between laboratories, so the range printed on your own report is the one to go by.
Why is the Vitamin B12 test done?
It is checked for anemia with large red cells, tiredness, tingling or numbness, memory problems, and in people on metformin or vegetarian diets.
What does a high Vitamin B12 level mean?
High B12 is usually from supplements or injections and is harmless. Very high levels without supplements can occasionally point to liver or blood disorders.
Common causes
- Supplements or B12 injections
- Liver disease
- Some blood disorders
Diet and lifestyle tips
- No action if you take supplements
- If not, ask your doctor whether further tests are needed
What does a low Vitamin B12 level mean?
Low B12 can cause anemia, tiredness, a sore tongue, pins and needles, balance problems and memory issues. Nerve damage can become permanent if it is not treated.
Common causes
- Vegetarian or vegan diet
- Long-term metformin or acid-reducing medicines (omeprazole, pantoprazole)
- Pernicious anemia (autoimmune)
- Stomach surgery or gut conditions
- Older age
Diet and lifestyle tips
- Eat B12 foods: meat, liver, fish, eggs, milk, yogurt, cheese
- Vegetarians and vegans need fortified foods or a supplement
- If absorption is the problem, injections may be needed
When should you see a doctor?
See a doctor if your B12 is low, especially with numbness, tingling or balance problems.
Last updated
This page is for general education and is not a diagnosis. Normal ranges differ between laboratories, so always compare your result with the reference range printed on your own report, and discuss abnormal results with your doctor.