Vitamin B12 in Serum

Cobalamin is a water soluble essential vitamin from animal foods, needed for red blood cell formation, DNA synthesis, and nerve function. Most circulating B12 is bound to inactive proteins.
Also known as:
S-B12
B12
Cobalamin
.

Vitamin B12 ranges

Interpret your result
"Normal" lab range for Vitamin B12 is between 232 and 1245 pg/mL:
232
1245
According to OptimalDX, Vitamin B12 should be between 545 and 1100 pg/mL:
545
1100
According to Campos et al. (2020), Vitamin B12 should be above 310 pg/mL:
310
Optimal range
Optimal range for Vitamin B12 appears to be between 500 and 1000 pg/mL:
0
200
500
1000
1100
1500
Why this optimal range?
Preliminary range is based on functional health organizations including but not limited to those listed above.

What a low value may mean:

Common reasons for low Vitamin B12:

  • Low B12 most often reflects inadequate intake (vegan or vegetarian diets, chronic alcohol use) or malabsorption.

    Malabsorption causes include pernicious anemia (autoimmune loss of intrinsic factor), celiac disease, Crohn’s disease, atrophic gastritis, low stomach acid, prior gastric or ileal surgery, inflammatory bowel disease, and H. pylori or small intestinal bacterial overgrowth.

    Common drug causes: long-term metformin, proton pump inhibitors, and H2 blockers.

    ,,

What a high value may mean:

Common reasons for high Vitamin B12:

  • High B12 is usually caused by B12 supplements or injections, which is generally not a concern since B12 is not considered toxic.

    When not intake-related, elevated B12 can accompany liver disease (cirrhosis, hepatitis, hepatocellular carcinoma, or liver metastases), kidney failure, diabetes, myeloproliferative and other hematological disorders (leukemia, polycythemia vera, hypereosinophilic syndrome), and other cancers (colon, pancreas, breast, stomach).

    Elevated serum B12 can also coexist with functional B12 deficiency, since the test also measures B12 bound to transport proteins that is not taken up by cells.

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