Laboratory test
Vitamin D
Other names and abbreviations: 25(OH)D, 25-hydroxyvitamin D
The level of vitamin D in the body. Deficiencies are very common in Poland, especially from October to April.
Vitamin D affects bones, muscles and immunity. The 25(OH)D test helps choose the supplement dose – both deficiency and excess are harmful.
Typical ranges in adults
| Parameter | Typical range | What a deviation may mean |
|---|---|---|
| 25(OH)D | 30–50 ng/ml | optimal level |
| 25(OH)D | 20–30 ng/ml | suboptimal |
| 25(OH)D | below 20 ng/ml | deficiency |
| 25(OH)D | above 100 ng/ml | risk of toxicity |
The ranges are approximate and differ between laboratories; they also depend on age, sex and pregnancy. A result outside the range doesn't always mean illness – discuss it with a doctor.
When it is done
With osteoporosis, chronic diseases, before starting high-dose supplementation and to monitor it.
How to prepare
Usually no special preparation is needed. In the morning before the blood draw, it's best not to eat a heavy breakfast – ask at reception.
