Vitamin D Test
A blood test that measures vitamin D (25-hydroxy vitamin D).
Quick Summary
To check for vitamin D deficiency in people with bone pain, weak bones or risk factors.
25-hydroxy vitamin D level.
No fasting needed.
Overview
Vitamin D is needed for calcium absorption and bone health.
Testing everyone isn't always needed; your doctor will advise.
What It Measures
25-OH vitamin D
The main form measured.
How It's Performed
- 01
Preparation
Usually no special preparation. Tell the staff about medicines you take.
- 02
Blood sample
A small amount of blood is taken from a vein in your arm with a thin needle.
- 03
Afterwards
Press on the spot for a minute. A small bruise is common; you can go back to normal activities.
Reference Ranges
Note: Normal ranges vary by laboratory. Consult your report for the specific reference used.
| Parameter | Typical Range (Adult) | Units |
|---|---|---|
| Deficient | Below 20 | ng/mL |
| Insufficient | 20–29 | ng/mL |
| Sufficient | 30–100 | ng/mL |
Interpreting Results & Next Steps
Discuss with Doctor
Normal ranges differ between laboratories, ages and sexes; always use the range printed on your report and ask your doctor what your results mean.
If values are Low:
Low levels can cause bone pain and weakness.
If values are High:
Very high levels usually come from too many supplements and can raise calcium.
Sources and further reading
Last updated 21 October 2026. For more detail, see these trusted health organisations.
- Vitamin D Test(opens in a new tab) · MedlinePlus, US National Library of Medicine