What Does Vitamin B12 (Cobalamin) Mean?
Vitamin B12 is essential for nerve function and red blood cell production. Deficiency is common in vegetarians, older adults, and people on acid-blocking medications.
What Vitamin B12 (Cobalamin) Measures
B12 is a water-soluble vitamin needed for DNA synthesis, the myelin sheath that insulates nerves, and red blood cell formation. Low B12 can cause anemia, fatigue, numbness, balance issues, and memory problems. If untreated, the nerve damage can become permanent.
Normal Ranges
Deficient< 200 pg/mL
Borderline200–300 pg/mL
Normal300–900 pg/mL
Functional optimum (some labs)> 400–500 pg/mL
Reference ranges may vary slightly by lab. Always use the range provided on your specific test report.
What Affects Your Vitamin B12 (Cobalamin) Level
- Vegetarian or vegan diet (B12 is naturally only in animal foods)
- Aging (reduced stomach acid lowers absorption)
- Proton pump inhibitors and metformin (impair absorption)
- Gastric bypass or GI surgery
- Pernicious anemia (autoimmune attack on intrinsic factor)
- Crohn's, celiac, or other malabsorption conditions