Vitamin B12 & Folate
B12 and folate are needed to build DNA. Without them the marrow makes red cells that are too large and too few, and B12 deficiency in particular can damage nerves and the spinal cord — sometimes before the blood count changes at all.
This is an educational reading aid, not a diagnosis and not medical advice. Reference ranges differ between laboratories — always read the range printed on your own report. Nothing here can see you, your history or your medicines. Do not start, stop or change any treatment on the strength of this page: take your report to a qualified doctor.
Reference ranges reviewed by Dr. Mohan Gayenlast reviewed
Your values
Fill in only the ones on your report. Anything you leave blank is simply skipped.
Serum vitamin B12 (cobalamin).
Serum folate (vitamin B9).
Enter one or more values and your reading will appear here.
What this panel is easy to get wrong
- NERVE DAMAGE FROM B12 DEFICIENCY CAN HAPPEN WITH A NORMAL BLOOD COUNT. Numbness, pins and needles, unsteadiness or memory change with a low-normal B12 should be discussed with a doctor rather than dismissed because the haemoglobin is fine.
- Never treat a combined deficiency with folate alone: correcting folate while B12 is still low can allow the neurological damage to continue. B12 is checked and replaced first.
- Metformin, long-term acid-suppressing medicines, a strict vegetarian or vegan diet, and stomach or bowel surgery all lower B12.
Where these ranges come from: Commonly published adult serum intervals.
Where this is written from: This site is written from Indian clinical practice. Drug availability and brand names, vaccination schedules, national health programmes and some reference cut-offs differ between countries — a schedule or a threshold that is standard here may not be standard where you are. If you are reading outside India, check anything on this page against your own country’s guidance before you act on it.
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The two vitamins whose lack makes red cells large.