A vitamin B12 test measures the level of vitamin B12 (cobalamin) in your blood to check for deficiency. B12 is needed to make red blood cells and keep nerves healthy. A typical adult normal range is about 200–900 pg/mL; levels below 200 pg/mL usually indicate deficiency. The test is especially relevant for vegetarians.
What does the vitamin B12 test measure?
Vitamin B12 does two big jobs: it helps your bone marrow make healthy red blood cells, and it maintains the protective coating around nerves. Your body cannot make B12; it comes almost entirely from animal foods such as milk, curd, paneer, eggs, fish and meat.
That is why B12 deficiency is particularly common in India, where many people are vegetarian or eat little dairy. Other common causes are:
- Long-term use of metformin (a common diabetes medicine) or acid-reducing tablets (PPIs such as pantoprazole or omeprazole).
- Reduced absorption with age, gut surgery or conditions such as pernicious anaemia.
- Regular heavy alcohol use.
Deficiency develops slowly, sometimes over years, because the liver stores B12. Symptoms can include:
- Tiredness and breathlessness from anaemia
- Tingling, numbness or “pins and needles” in hands and feet
- Memory problems, low mood or poor concentration
- A sore, smooth tongue or mouth ulcers
Nerve symptoms can become permanent if deficiency is left untreated for long, so early testing matters.
Vitamin B12 normal range
(roughly 148–664 pmol/L)
Where does your result fall?
Enter your Vitamin B12 value from your report.
A general guide, not a diagnosis. The reference range on your own report takes priority, and a doctor should interpret any result outside it.
Lab ranges vary noticeably (some report up to 1,100 pg/mL as normal). Ranges vary between labs and methods. Always compare your result with the reference range printed on your own report.
What abnormal results can mean
- Low B12: Suggests deficiency, from diet, absorption problems or medicines. Your doctor decides between tablets and injections.
- High B12 without supplements: Less common; occasionally linked to liver or blood conditions and worth discussing with a doctor.
Who should get this test?
- Vegetarians and vegans, especially those who eat little dairy.
- People taking metformin or acid-reducing tablets for more than a year.
- Adults over 50.
- Anyone with symptoms: tingling or numbness, unexplained fatigue, memory changes, or anaemia with large red cells (high MCV) on a CBC.
- Preparation: Usually no fasting needed, though some labs prefer 6–8 hours. Mention any B12 supplements or injections you take.
This page is for general information and is not a substitute for medical advice. Always interpret your results with a qualified doctor.