Vitamin B12 Test
A blood test that measures vitamin B12, important for nerves and red blood cells.
Quick Summary
To check for B12 deficiency in people with anaemia, tingling, memory problems or risk factors.
Vitamin B12 level.
Usually no preparation; stop B12 supplements before the test if advised.
Overview
Low B12 is common in vegetarians and people taking metformin or acid reducers.
It's often tested with folate and a blood count.
What It Measures
Vitamin B12
Blood level.
How It's Performed
- 01
Preparation
Usually no special preparation. Tell the staff about medicines you take.
- 02
Blood sample
A small amount of blood is taken from a vein in your arm with a thin needle.
- 03
Afterwards
Press on the spot for a minute. A small bruise is common; you can go back to normal activities.
Reference Ranges
Note: Normal ranges vary by laboratory. Consult your report for the specific reference used.
| Parameter | Typical Range (Adult) | Units |
|---|---|---|
| Vitamin B12 | 200–900 | pg/mL |
Interpreting Results & Next Steps
Discuss with Doctor
Normal ranges differ between laboratories, ages and sexes; always use the range printed on your report and ask your doctor what your results mean.
If values are Low:
Low B12 can cause anaemia and nerve damage.
If values are High:
High levels are uncommon and usually not a problem.
Sources and further reading
Last updated 21 October 2026. For more detail, see these trusted health organisations.
- Vitamin B Test(opens in a new tab) · MedlinePlus, US National Library of Medicine