Vitamin B12
Disclaimer: Information on this page is for educational purposes. Consult a physician to interpret your test results. Lissa Health helps track biomarker trends but does not replace medical advice.
What This Test Measures
Vitamin B12 is essential for DNA synthesis and myelin. Deficiency causes megaloblastic anemia and neuropathy.
Serum B12 may be normal with tissue deficiency — check MMA and homocysteine.
Normal Ranges
| Group | Reference Range |
|---|---|
| Men | 200–900 pg/mL |
| Women | 200–900 pg/mL |
| Children | 200–900 pg/mL |
Reference ranges may vary by laboratory and assay method.
Causes of High Levels
- Supplementation
Causes of Low Levels
- Vegan diet
- Pernicious anemia
- Malabsorption
- Long-term metformin
- Gastric surgery
Test Preparation
- Report supplements and metformin
Related Biomarkers
| Biomarker | Relationship |
|---|---|
| Folate | Megaloblastic panel |
| Mean Corpuscular Volume (MCV) | Macrocytosis |
| Hemoglobin | Anemia |
FAQ
How often should I take this test?
At-risk groups — annually.
What should I do if my result is abnormal?
Low B12 with neurologic symptoms — urgent treatment.
Last updated: June 2026