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Health Check

Vitamin B12 (cobalamin) – B12 status

Cobalamin (vitamin B12) is measured for fatigue, tingling in the hands and feet, difficulty concentrating, and anaemia. Deficiency is more common with a vegetarian or vegan diet, old age, and in certain stomach diseases.

What is Vitamin B12 (cobalamin)?

B12 is a vitamin the body needs to form red blood cells and for the function of the nervous system. It is found almost exclusively in animal foods and is absorbed in the lower part of the small intestine.

Why is Vitamin B12 (cobalamin) measured in a health check?

B12 deficiency develops slowly and can cause both anaemia and neurological symptoms. The test is often analysed along with folate and homocysteine, which rises during deficiency.

High and low values

High value: High values are usually due to supplements and generally lack clinical significance, but in rare cases can be seen in liver or blood diseases.

Low value: Low values indicate B12 deficiency and can cause fatigue, tingling, poorer memory, sore corners of the mouth, and anaemia with enlarged red blood cells.

Reference ranges differ between laboratories, sexes and ages and are stated in your result. The information here does not replace medical assessment.

How B12 is measured in a health check

Vitamin B12 (cobalamin) is analysed from a standard blood test with no fasting required. The liver has large stores, which means a deficiency can build up over several years before it shows up in the blood or causes symptoms. This is one reason the marker is included in broad health checks — it catches a slow process that would otherwise easily be missed.

If you take B12 supplements or have had injections, the value will be high and hard to interpret. If you want to know your own level, supplements should have been paused for a while, and this should be done in consultation with a doctor if you're being treated for a diagnosed deficiency.

Common causes of B12 deficiency

B12 is found almost exclusively in animal foods and also requires proper absorption in the stomach and small intestine. Both intake and absorption can fail.

  • Vegetarian or vegan diet without supplements
  • Atrophic gastritis and pernicious anaemia, where intrinsic factor is lacking
  • Long-term treatment with proton pump inhibitors or metformin
  • Coeliac disease, Crohn's disease or previous stomach or bowel surgery
  • Old age, where absorption generally declines
  • High alcohol consumption

Symptoms and complementary tests

B12 is needed for both blood formation and the nervous system. Deficiency can cause fatigue, tingling and numbness in hands and feet, worse balance, forgetfulness, low mood and a burning tongue. Nerve symptoms can appear before haemoglobin is affected, meaning a person with normal haemoglobin can still have a significant deficiency.

At borderline values, B12 is often supplemented with homocysteine or methylmalonic acid (MMA), which rise early when there's a deficiency at the cellular level. Folate is usually analysed at the same time since the deficiencies resemble each other and often occur together, and MCV in a full blood count can show enlarged red blood cells.

After the result

A confirmed deficiency is usually treated with high-dose tablets or injections, depending on the cause. Haemoglobin responds quickly while nerve symptoms can take months to improve — and some remain if the deficiency has been present for a very long time, which is a strong argument for checking B12 early in a health check. Follow-up testing is usually done after two to three months, and thereafter according to the care provider's recommendation.

Frequently asked questions about Vitamin B12 (cobalamin)

What symptoms does B12 deficiency cause?

Common symptoms include fatigue, tingling or numbness in the hands and feet, difficulty concentrating, sore corners of the mouth, and anaemia. Symptoms often come on gradually.

Who is at the greatest risk of B12 deficiency?

The risk is higher with a vegetarian or vegan diet, old age, stomach or intestinal surgery, atrophic gastritis, and with long-term treatment with metformin or acid-inhibiting drugs.

Why is folate measured together with B12?

B12 and folate work together in the formation of red blood cells and cause similar types of anaemia. Measuring both makes it possible to see which deficiency is causing the symptoms.

Do vegans need to check B12 more often?

Yes. Without animal foods, supplements are required, and an annual check is reasonable to make sure the dose is sufficient.

Can you have B12 deficiency with normal haemoglobin?

Yes. Nerve symptoms can appear before haemoglobin is affected, so it isn't enough to look at haemoglobin alone.

What's the difference between B12 and folate?

Both are needed for blood formation and deficiency gives a similar blood picture, but only B12 deficiency causes typical nerve symptoms. This is why they're usually analysed together.

Health checks that include Vitamin B12 (cobalamin)

Vitamin B12 (cobalamin) is included in 9 of Labkollen's health checks. Analysis name in the result: Kobalamin (B12).

  • Man +

    49 markers

    Labkollens mest omfattande kontroll för män – inklusive testosteron, PSA och hjärt-kärlmarkörer.

    2 195 krMed prenumeration (årlig hälsokontroll): 1 756 kr

    See the test

  • Kvinna +

    44 markers

    Labkollens mest omfattande kontroll för kvinnor – inklusive järnstatus, sköldkörtel och hormoner.

    2 195 krMed prenumeration (årlig hälsokontroll): 1 756 kr

    See the test

  • Standard

    37 markers

    Bred hälsokontroll över blodsocker, blodfetter, blodvärde, lever, njurar, sköldkörtel och vitaminer.

    1 895 krMed prenumeration (årlig hälsokontroll): 1 516 kr

    See the test

  • Seniorkollen

    32 markers

    Anpassad kontroll för dig över 65 med fokus på hjärta, njurar, sköldkörtel och näringsstatus.

    1 399 krMed prenumeration (årlig hälsokontroll): 1 119 kr

    See the test

  • Gravid

    26 markers

    Kontroll under graviditet – blodvärde, järn, sköldkörtel, vitaminer och hCG.

    1 199 krMed prenumeration (årlig hälsokontroll): 959 kr

    See the test

  • Vitamin- och mineralkollen

    18 markers

    D-vitamin, B12, folat, järn och mineraler för dig som vill kolla näringsstatus.

    1 199 krMed prenumeration (årlig hälsokontroll): 959 kr

    See the test

  • Uthållighetssport

    16 markers

    För löpare, cyklister och simmare – järnstatus, energiomsättning och återhämtning.

    1 599 krMed prenumeration (årlig hälsokontroll): 1 279 kr

    See the test

  • Hårkollen

    13 markers

    Markörer kopplade till håravfall: järn, zink, D-vitamin, B12 och hormoner.

    1 099 krMed prenumeration (årlig hälsokontroll): 879 kr

    See the test

  • Mag- och tarmkollen

    13 markers

    Kalprotektin, glutenantikroppar och näringsstatus vid magbesvär.

    1 199 krMed prenumeration (årlig hälsokontroll): 959 kr

    See the test

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Guides covering Vitamin B12 (cobalamin)

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Responsible for the content: Mathias Khemiri, Oftamed Sverige AB.

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