What is Vitamin B12?
needed for nerves and red cells
Vitamin B12 is needed for red cell formation and nerve function. Deficiency is more common in vegans, older people, and those with certain stomach conditions.
B12 is found only in animal foods and is absorbed through a specific mechanism in the stomach lining. Low stomach acid or atrophic gastritis impairs absorption.
Test facts
- Unit
- pmol/L
- Sample
- Serum
- Fasting
- No fasting needed
- Turnaround
- 2 days
What does low Vitamin B12 mean?
Low B12 produces fatigue, tingling in hands and feet, difficulty concentrating, and in severe cases anaemia. Holotranscobalamin (active B12) is a more sensitive measure.
What does high Vitamin B12 mean?
High B12 most often follows supplementation or injection and is usually not a clinical concern.
Panels that measure Vitamin B12
- Deep Baseline
- Female Annual
- Male Annual
- Hormone+
- Pre-Conception
- Iron & Anaemia
- Core Vitamins
- Vitamins & Minerals Full
- Athlete Performance
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This is general information about the marker, not an assessment of your values and not medical advice. Last updated: May 2026.