Vitamin B12 (cobalamin) plays a role in the production of red blood cells and the functioning of the nervous system. A test gives insight into your B12 level, with personal explanation from our doctors.
Interpreted by BIG-registered doctors
Achtergrond
Vitamin B12 (cobalamin) is a water-soluble vitamin needed by the body for the production of red blood cells, the functioning of the nervous system, and DNA synthesis. B12 is found almost exclusively in animal products such as meat, fish, eggs, and dairy.
B12 is absorbed in the stomach with the help of a protein called intrinsic factor. People following a vegetarian or vegan diet, older adults, people with gastrointestinal conditions, or those who have had gastric surgery have an increased risk of a lower B12 status. The standard measurement of total B12 gives an initial picture; for borderline values or suspected functional deficiency, additional testing (such as Holo-TC, MMA, or homocysteine) may be worthwhile.
In het kort
Cobalamin
Water-soluble B vitamin
Animal sources
Meat, fish, eggs, dairy
Gastric absorption
Requires intrinsic factor
Blood & nerve
Essential for both
Veelvoorkomende redenen om te meten
Hieronder enkele situaties waarin een meting van Vitamin B12 inzicht kan bieden.
A test gives a baseline for your vitamin B12 level.
Vitamin B12 is found almost exclusively in animal products, on a plant-based diet without supplementation, status is at risk.
Those taking B12 supplements or injections can periodically test whether their level is satisfactory.
The absorption of B12 from food decreases with age; a test gives insight into whether the level is sufficient.
In coeliac disease, Crohn's disease, or with long-term use of proton pump inhibitors, B12 absorption may be reduced.
A low B12 level is sometimes associated with complaints of fatigue or difficulty concentrating.
Wat betekent uw uitslag
Vitamin B12 is measured in picomoles per litre (pmol/L). Interpretation of your value is carried out against the standard reference ranges. For borderline cases or specific questions, additional testing can provide more information.
A low B12 level indicates a deficiency. Possible causes include a diet low in animal products, reduced absorption from the gut, or certain medications. Supplementation through diet, supplements, or (for absorption problems) injections is a common approach.
B12 within the reference range gives a reassuring picture. For borderline values, especially at the lower end, additional testing (Holo-TC or homocysteine) can clarify whether a functional deficiency is present.
An elevated B12 level is often seen with active supplementation and is usually not harmful, excess B12 is excreted in the urine. For significantly elevated values without supplementation, our doctor provides explanation and context.
Hoe wij uw uitslag interpreteren
Our doctors interpret your B12 against the reference ranges of the laboratory and your personal context. You receive a report in plain language, as a starting point for your own insight or a conversation with your healthcare provider.
Related tests
A single marker gives one perspective. For a broader picture you can combine Vitamin B12 with a theme package or related markers.
Veelgestelde vragen
No, you do not need to fast for a B12 measurement.
Total B12 measures all B12 in the blood. Holo-TC (active B12) measures only the portion that is biologically available to the cells. For borderline cases or suspected functional deficiency, Holo-TC can provide additional information.
For a baseline measurement, it is sometimes recommended to stop supplementation for 2–4 weeks. For active B12 injections, a longer waiting period is often advised. You may wish to discuss this with our doctor via customer service.
B12 is found mainly in meat, fish, eggs, and dairy. Plant-based foods contain virtually no B12, fortified plant-based milk alternatives and supplements are therefore an important source on a plant-based diet.
A single measurement is sufficient for initial insight. With active supplementation or as follow-up to a low baseline, re-testing after 3 to 6 months is common.
Homocysteine is an amino acid that the body breaks down with the help of B12, B6, and folic acid. With a functional B12 deficiency, homocysteine can be elevated even when the B12 blood level still falls within the reference range.
You will receive a PDF report with your value and explanation. What you do with it, such as discussing it with your GP, adjusting your diet, or taking no action, remains entirely your choice.
Yes, the report is written in medical language and contains all relevant laboratory information.
In the Health Guide
For €69 you receive your B12 level including personal explanation from a doctor, typically within 2 business days. No referral required.
Order Vitamin B12 for €69 →Want to test multiple markers at once?
Combine Vitamin B12 with other markers via Bloodworks Select. Blood draw costs are waived from €225.
Customer service
Available on weekdays from 9:00 – 17:00
