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Vitamin B12: Normal Values & Interpretation
Here’s a breakdown of Vitamin B12 levels, based on the provided text:
Key Concepts:
- Cobalamins: Vitamin B12 consists of various chemical compounds called cobalamins, known for their red color.
- Active Forms: Methylcobalamine and adenosylcobalamine are the forms the body can use.
- Status Markers: Indicate the amount of B12 present.
- Serum Vitamin B12: Measures total B12 in the blood (active & inactive).
- Holotranscobalamin (Holo-TC): Measures the active form of B12. Considered an early indicator of deficiency.
- Functional Markers: Indicate how well B12 is working in the body.
- Methylmalonic Acid (MMA): Increases when B12 is low.
- Homocysteine: Increases when B12 (and folate) are low; a risk factor for cardiovascular disease.
Normal Ranges & Target Values:
| Marker | Reference Range | Target Value |
|---|---|---|
| Serum Vitamin B12 | 200 – 2000 pg/ml | > 1000 pg/ml |
| Long-term Goal | 700 – 900 pg/ml | |
| Holotranscobalamin | > 37.5 – 150 pmol/l | > 100 pmol/l |
| Homocysteine | (Range not fully provided in text – incomplete data) |
Important Notes:
- A normal serum B12 level doesn’t always mean sufficient B12, as it includes inactive forms.
- Holo-TC is a more sensitive marker for deficiency.
- Increased B12 levels after supplementation (oral or injection) are not harmful and indicate successful treatment.
- Functional markers (MMA & Homocysteine) provide insight into how the body is utilizing B12.
