Vitamin B12 pg/mL → pmol/L
Convert vitamin b12 from pg/mL to pmol/L
Sources last checked: 2026-11-03
Vitamin B12 pg/mL → pmol/L
Convert vitamin b12 from pg/mL to pmol/L
Converts units only; reference ranges depend on the laboratory, the assay and the patient.
What is the Vitamin B12 pg/mL → pmol/L?
Total serum vitamin B12 (cobalamin) is reported in pg/mL — identical to ng/L — in Turkey, the USA and many German and Austrian laboratories, and in pmol/L in many other European laboratories. This converter multiplies by 0.7378, based on the molar mass of cyanocobalamin (1355.4 g/mol). The circulating forms (methyl-, adenosyl- and hydroxocobalamin) have slightly different molar masses, so the conversion is a convention rather than an exact stoichiometric statement.
When to use it
- Comparing a B12 result in pg/mL or ng/L with literature or guidelines that use pmol/L
- Following B12 over time across laboratories with different units
- Reading British or Scandinavian reports, which often use ng/L or pmol/L
- Exam questions on megaloblastic anaemia or neuropathy work-up
When not to use it
- Holotranscobalamin ("active B12"), which is a different test, usually reported directly in pmol/L
- Methylmalonic acid or homocysteine, which are functional markers with their own units
- Ruling B12 deficiency in or out from total B12 alone
How it is calculated
Vitamin B12 (pmol/L) = vitamin B12 (pg/mL) × 0.7378
Clinical pearls and limitations
- Converts units only; reference ranges depend on the laboratory, the assay and the patient.
- 1 pg/mL = 1 ng/L ≈ 0.738 pmol/L; 350 pg/mL ≈ 258 pmol/L.
- Total B12 includes cobalamin bound to haptocorrin, which is not available to cells; a normal-looking value does not exclude functional deficiency.
- Anti-intrinsic-factor antibodies can interfere with some competitive-binding immunoassays and produce falsely normal or high results.
- Reference intervals and decision limits differ between assays and laboratories; use the reporting laboratory's values.
Frequently asked questions
How do I convert vitamin B12 from pg/mL to pmol/L?
Multiply by 0.7378. For example, 350 pg/mL × 0.7378 = 258 pmol/L and 600 pg/mL × 0.7378 = 443 pmol/L.
Is pg/mL the same as ng/L for B12?
Yes. 1 pg/mL = 1 ng/L, so a value in ng/L converts with exactly the same factor.
Why does the converter use cyanocobalamin's molar mass?
It is the convention used in SI conversion tables. Assays measure a mixture of cobalamins with slightly different masses, so the factor is a standard approximation.
Evidence and guidelines
Have a follow-up question?
Medelix answers clinical questions from current guidelines and studies — every statement with its source.
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<p><a href="https://medelix.ai/en/calculators/vitamin-b12-pg-ml-to-pmol-l">Vitamin B12 pg/mL → pmol/L calculator by Medelix</a></p>For healthcare professionals and medical students. These tools support, and do not replace, clinical judgement. Always check results against the original source and your local protocols.