B12 Deficiency
Symptoms and normal levels.
For serum B12, below 200 pg/mL is deficiency and 200–300 pg/mL is borderline. Convert: pg/mL × 0.738 = pmol/L.
| Status | pg/mL | pmol/L |
|---|---|---|
| Deficiency | <200 | <148 |
| Borderline (confirm with MMA) | 200–300 | 148–221 |
| Sufficient | ≥300 | ≥221 |
- NIH Office of Dietary Supplements — Vitamin B12
- British Society for Haematology — cobalamin and folate guideline (2014)
General information only; not diagnosis or treatment. Review your results with your clinician.
