Vitamin B12
Vitamin B12 is needed to make red blood cells and for the nervous system. It comes from animal foods.
At a glance
- Sample
- Blood
- Units
- pg/mL (US), pmol/L (Europe)
- Often looked at with
- Vitamin D, 25-OH, Folate
- Preparation
- You may be asked not to eat for a few hours before the test.
Units: pg/mL and pmol/L
US labs usually print vitamin B12 in pg/mL, most European labs in pmol/L. To convert, divide pg/mL by 1.3554.
pmol/L = pg/mL ÷ 1.3554 · molar mass 1355.37 g/mol
This converter changes units only. It doesn’t tell you whether a number is in or out of any range: that depends on the range printed by your own lab, and on your doctor. Soma does not diagnose and is not medical advice.
Why lab ranges differ
Each lab sets its reference range for its own method and analyser, and many ranges differ by age and sex. Two labs can print different ranges for the same blood, so a result is read against the range on its own report, not against a number from another lab or a website.
Soma charts every vitamin B12 result against the range printed by the lab that measured it.
What can affect the result
- B12 supplements shortly before the test.
- Pregnancy lowers it without meaning a deficiency.
- Biotin supplements can skew some methods.
If something like this applies, mention it to the doctor who reads your results.
Questions
How do I convert vitamin B12 from pg/mL to pmol/L?
Divide pg/mL by 1.3554. For example, 400 pg/mL is 295.1 pmol/L.
Why does my lab’s vitamin B12 range differ from another lab’s?
Each lab sets its range for its own method and equipment, and many ranges differ by age and sex. That’s why a result is best read against the range printed on the same report.
How do I prepare for a vitamin B12 test?
You may be asked not to eat for a few hours before the test. Follow your lab’s instructions.
Related tests
Got a lab report with Vitamin B12?
Share it to Soma: it reads every row on your phone, with no account and no upload, and puts your vitamin B12 on one chart with your earlier results, each against the range your lab printed.
Sources
- Vitamin B Test — MedlinePlus, U.S. National Library of Medicine.
- Units: PubChem: Cyanocobalamin (cyanocobalamin), molar mass 1355.37 g/mol, as the Soma app converts.
Mention of a source doesn’t mean it endorses Soma. This page explains the test; it doesn’t diagnose and is not medical advice. Talk to your doctor about what your results mean.