Vitamin B12 (Cobalamin)

Normal range 200–900 pg/mL (148–664 pmol/L SI). Specimen: Serum.

Also known as: cobalamin, B12.

200–900 pg/mLReference range

Reference range

Conventionalpg/mL

200900

SIpmol/L

148664

Specimen	Serum
Conventional range	200–900 pg/mL
SI range	148–664 pmol/L
Conversion factor	×0.738 (conventional → SI)
Panel	Inflammatory & Other Chemistry

Convert any Vitamin B12 (Cobalamin) result between units on the unit converter.

What is the normal range for Vitamin B12 (Cobalamin)?

The standard teaching reference range for Vitamin B12 (Cobalamin) is 200–900 pg/mL in conventional units, or 148–664 pmol/L in SI units. This value is measured in serum.

Source: Adult reference values compiled from Pagana & Pagana, Mosby's Diagnostic and Laboratory Test Reference, and Fischbach & Dunning, A Manual of Laboratory and Diagnostic Tests. Reference ranges vary by laboratory, method, age, sex, and population — always use the range printed on the actual result.

Above the range

Common causes of a high Vitamin B12 (Cobalamin)

Supplementation
Liver disease
Myeloproliferative disorders

Below the range

Common causes of a low Vitamin B12 (Cobalamin)

Pernicious anemia
Vegan diet
Malabsorption
Metformin or PPI use

At the bedside

Nursing considerations

Deficiency causes macrocytic anemia and irreversible neuropathy if untreated.
Check with folate; giving folate alone can mask B12 deficiency while nerves worsen.

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