Understanding your Vitamin B12 (Cobalamin) results
Vitamin B12 (cobalamin) is a water-soluble vitamin the body needs to make DNA, to form red blood cells and to maintain the myelin sheath that insulates nerves. The serum B12 test measures the amount circulating in the blood, in picograms per millilitre (pg/mL) or picomoles per litre (pmol/L). The liver stores B12, so a deficiency tends to develop slowly.
The ranges on this page are commonly quoted adult reference ranges. Laboratories set their own, so the range printed on your report is the one that applies to your result.
Commonly quoted adult reference ranges
>>>| Parameter | Reference range | Unit |
|---|---|---|
| Band often labelled deficient | < 200 | pg/mL |
| Band often labelled borderline | 200–300 | pg/mL |
| Usual reference range | 300–900 | pg/mL |
| Above the usual range | > 900 | pg/mL |
What a high Vitamin B12 (Cobalamin) result can mean
A B12 result above the reference range often reflects recent supplements or a diet rich in meat, fish or dairy. Less often, a high level in someone who takes no supplements is seen with liver disease or some blood disorders, so a doctor may look at liver function tests and a full blood count alongside it.
What a low Vitamin B12 (Cobalamin) result can mean
Low B12 is associated with two main problems. The first is megaloblastic anaemia, in which red blood cells are larger than usual (macrocytes) and carry oxygen less well, causing tiredness, pallor and breathlessness. The second is nerve damage: numbness or tingling in the hands and feet (peripheral neuropathy), and sometimes problems with balance or memory. Nerve symptoms can appear before anaemia does. B12 comes from animal products, so a low result is more likely in people who eat little or none of them. Metformin can also reduce the amount of B12 the gut absorbs.
How a doctor reads the result
A doctor will usually interpret a B12 result alongside your symptoms, diet, medicines and full blood count. Numbness, tingling or a sore, red tongue (glossitis) are details a doctor will want to know about when reading a low result. Discuss the result with your doctor.
Follow-up a doctor may arrange
If B12 is low, a doctor may look for the cause, including diet and absorption from the gut, and may order a full blood count and folate. How a low level is treated, and for how long, is decided by the doctor. A repeat test is often used to check the response.
Related tests
>>>Vitamin B12 (Cobalamin): preparation and listed prices
No fasting is needed. Sample type: blood. The Vitamin B12 test is listed at AED 80 to AED 149 across 5 labs and services: AED 80 on the Smart Care Polyclinic website (Dubai only), AED 89 on the DarDoc website, AED 100 on the Healthchecks360 website, AED 110 on the Unilabs website and AED 149 on the ServiceMarket website (Dubai only, home visit included).
Sources: Prices on this page are the ones each lab or service publishes on its own website, read between 13 October 2026 and 7 November 2026. Zavis has published prices from 6 of the 13 labs and services it lists: of the other 7, 6 do not publish per-test prices and 1 website could not be read. The websites do not all say whether VAT or a collection fee is added to a listed price, so confirm the price with the lab before you book. How Zavis sources prices.
Listed prices for the Vitamin B12 test, as each site names itFrequently asked questions
What are the commonly quoted reference ranges for Vitamin B12 (Cobalamin)?
Commonly quoted adult reference ranges are: Band often labelled deficient: < 200 pg/mL; Band often labelled borderline: 200–300 pg/mL; Usual reference range: 300–900 pg/mL; Above the usual range: > 900 pg/mL. Laboratories set their own ranges, so the range printed on your report is the one that applies to your result.
What can a high Vitamin B12 (Cobalamin) result mean?
A B12 result above the reference range often reflects recent supplements or a diet rich in meat, fish or dairy. Less often, a high level in someone who takes no supplements is seen with liver disease or some blood disorders, so a doctor may look at liver function tests and a full blood count alongside it.
Is fasting needed for Vitamin B12 (Cobalamin)?
No fasting is needed. Sample type: blood.
How often are Vitamin B12 (Cobalamin) results rechecked?
There is no single interval that suits everyone. A doctor can advise whether and how often to test, based on your health, any treatment and your earlier results.
Medical disclaimer: The information on this page is provided for general educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Reference ranges are general guidelines. Your doctor will interpret your results in the context of your full clinical picture, symptoms, and medical history. If you have concerns about your test results, always consult a licensed healthcare professional. Do not delay seeking medical advice or disregard professional medical guidance because of information on this page.