Skip to content
Health Check

Vitamin D (25-OH) – D vitamin status

Vitamin D 25-OH shows your vitamin D status. Deficiency is common in northern latitudes during the winter months and can contribute to fatigue, muscle weakness, and poorer bone health.

What is Vitamin D (25-OH)?

25-OH-vitamin D is the form of vitamin D that circulates in the blood and best reflects the body's total supply from sun, diet, and supplements.

Why is Vitamin D (25-OH) measured in a health check?

At our latitude, almost no vitamin D is formed in the skin between October and March. The test is taken for fatigue, aches, repeated infections, dark skin tone, full-body covering, or little time spent outdoors.

High and low values

High value: Very high values are practically only seen with high doses of supplements and can affect calcium balance.

Low value: Low values mean vitamin D deficiency, which can cause fatigue, muscle weakness, aches, and, in the long term, deteriorated bone health.

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

How vitamin D is measured in a health check

Vitamin D is measured as 25-OH vitamin D in a standard blood test and requires no fasting. The level reflects the past few weeks' supply from both sun and diet or supplements. The test can be taken at any time of day.

In Sweden the value varies greatly with the season. Between October and March the sun is too low in the sky for the skin to produce vitamin D, which means many people have their lowest levels in February and March. If you want to know your lowest level, take the test late in winter; if you want to see your highest, take it after summer. If comparing values between years, it's best to take the test at the same time of year.

Who is at greatest risk of low levels?

Vitamin D deficiency is more common in the Nordic countries than in many others, and some groups have a clearly higher risk.

  • People with dark skin, who need more sun exposure for the same production
  • People who cover their skin or spend little time outdoors
  • Older adults, since the skin's ability to produce vitamin D decreases with age
  • People who eat little fatty fish, eggs or fortified dairy products
  • People who are overweight, where vitamin D is stored in fat tissue
  • People with gastrointestinal disease or after bariatric surgery, with reduced absorption

Symptoms and what a low value means

Vitamin D is needed for calcium absorption and thus for bones and muscles. Marked deficiency can cause muscle weakness, bone pain and fatigue, but mild deficiency often causes no clear symptoms at all. This is why vitamin D is a common marker in health checks: it can't be guessed at without a blood test.

A low value is usually addressed with supplements during the winter half of the year, and the effect can be followed up with a new test after about three months. Very high values should be avoided since prolonged overdosing can raise calcium levels in the blood — so check your level if you take high doses regularly.

How often should the test be taken?

For most people, a check as part of a health check every other year is enough, ideally late in winter. If you've had a deficiency and started supplements, a follow-up after three months is reasonable, and thereafter once a year for as long as treatment continues.

Frequently asked questions about Vitamin D (25-OH)

When during the year should vitamin D be measured?

Late winter and early spring give the lowest value and thus the most useful check. A sample taken after the summer usually shows the highest level during the year.

Can you have vitamin D deficiency without symptoms?

Yes. Many people have low values without clear issues, which is one reason vitamin D is included in several broad health checks.

Should I take supplements if the value is low?

Treatment and dosage are determined based on the value and your situation. Use the test result as a basis for contact with healthcare providers instead of self-dosing high doses.

What time of year is best for measuring vitamin D?

Late in winter, around February to March, shows your lowest level of the year. This is the most informative time if you want to know whether you need supplements.

How long does it take before supplements raise the value?

Most people see a clear increase after eight to twelve weeks of regular intake. Take the follow-up test no sooner than three months later.

Can you get too much vitamin D?

Yes, with high doses over a long period. Excess can raise calcium levels in the blood, so check your level if you take more than the recommended dose.

Health checks that include Vitamin D (25-OH)

Vitamin D (25-OH) is included in 9 of Labkollen's health checks. Analysis name in the result: Vitamin D-25-OH.

  • 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

  • Gymnastik och konståkning

    14 markers

    För teknikidrotter – benhälsa, järnstatus, sköldkörtel och tillväxtmarkörer.

    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

  • D-Vitaminkollen

    1 markers

    Enskilt prov på D-vitamin – vanligt lågt under vinterhalvåret.

    549 krMed prenumeration (årlig hälsokontroll): 439 kr

    See the test

Unsure which test you need? Start the test guide

Guides covering Vitamin D (25-OH)

Källor

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

Så här väljer vi källor, granskar innehållet och rättar fel: redaktionell policy.

Last updated: