Insight into your vitamin B12 level.
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.
Also known as: cobalamin, active B12, holoTC
Personal assessment by our BIG-registered doctors
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Blood draw
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Securely, typically within 2 working days from our physicians
Background
What is vitamin B12?
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 brief
Cobalamin
Water-soluble B vitamin
Animal sources
Meat, fish, eggs, dairy
Gastric absorption
Requires intrinsic factor
Blood & nerve
Essential for both
This marker is also included in
Testing several values in a single draw takes one blood collection and gives a more complete picture. The choice is yours.
Common reasons to test
When can insight into your Vitamin B12 be valuable?
Below are some situations in which measuring Vitamin B12 can provide insight.
Insight into your B12 status
A test gives a baseline for your vitamin B12 level.
With a vegetarian or vegan diet
Vitamin B12 is found almost exclusively in animal products, on a plant-based diet without supplementation, status is at risk.
Tracking the effect of supplementation
Those taking B12 supplements or injections can periodically test whether their level is satisfactory.
At an older age
The absorption of B12 from food decreases with age; a test gives insight into whether the level is sufficient.
With gastrointestinal conditions
In coeliac disease, Crohn's disease, or with long-term use of proton pump inhibitors, B12 absorption may be reduced.
With questions about energy or concentration
A low B12 level is sometimes associated with complaints of fatigue or difficulty concentrating.
What your result means
Vitamin B12 too low or too high: what does your result mean?
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 value
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.
A normal value
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.
A high value
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.
How we interpret your result
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
Often combined with Vitamin B12.
A single marker gives one perspective. For a broader picture you can combine Vitamin B12 with a theme package or related markers.
+ €29 blood draw fee per orderFree from €225
Frequently asked questions
Everything you want to know
Do I need to fast for a B12 test?
No, you do not need to fast for a B12 measurement.
What is the difference between total B12 and Holo-TC?
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.
How long should I stop taking B12 supplements for a reliable measurement?
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.
Which foods contain a lot of B12?
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.
How often should I measure B12?
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.
What is the difference with homocysteine?
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.
What do I do with my result?
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.
Can I share my report with my GP?
Yes, the report is written in medical language and contains all relevant laboratory information.
In the Health Guide
Read more about this value
Ready for insight into your vitamin B12 status?
You receive your B12 level including personal explanation from a doctor, typically within 2 working days. No referral required.
Order Vitamin B12 →Want to test multiple markers at once?
Combine Vitamin B12 with other markers via Bloodworks Select. The blood draw and collection fee is charged once per order, and is waived from €225.
30,-
+ €29 blood draw fee+ €29 blood draw fee per order