How reports print it
What it shows
25(OH)D is the form of vitamin D used to assess the body’s store of it.
Units and conversion
Base unit: ng/mL.
- 1 nmol/L = 0.4006 ng/mL · 1 ng/mL = 2.496 nmol/L
Typical ranges
Your laboratory’s range comes first — it is printed on the report next to the result.
There is no general reference here — compare with the range from your report.
Good to know
Societies disagree on thresholds. The Russian Association of Endocrinologists (2016) uses categories: below 20 ng/mL, 20–30 and 30 and above. The Endocrine Society (2024) suggests against routine 25(OH)D testing in healthy adults and sets no target levels for them. Helix prints 30–100 ng/mL and notes that values depend on the test system. So there is no general reference here: only the range from the report is used. Conversion: nmol/L ÷ 2.496 = ng/mL.
Why it can be higher
Common reasons discussed with a doctor. This is not a diagnosis.
- Taking vitamin D medicines in large amounts
Why it can be lower
- Little sun, especially in winter and at northern latitudes
- Darker skin
- Little vitamin D in the diet
- Poor absorption in the gut
What to ask a doctor
- Do I have a reason for this test?
- Which reference does my laboratory use, and why?
Whom to see
A GP or internist; then an endocrinologist.