Vitamin D Test: What It Shows and What It Does Not
Quick answer: A 25 hydroxy vitamin D test shows your vitamin D status from food, supplements and sun. It is useful when there is a reason to check, but routine testing for everyone is not recommended.
About this test
The test measures 25 hydroxy vitamin D (25(OH)D), the form your liver makes and the most reliable marker of vitamin D status. The total number includes vitamin D2 and D3.
Why is it ordered?
- Looking at bone pain, muscle weakness, fractures or low bone density.
- Checking people at higher risk, such as those with little sun exposure, poor nutrition, weight loss surgery, malabsorption, kidney or liver disease, or certain medicines.
- Following vitamin D supplements.
- Looking at general nutrition with fatigue or hair concerns, usually with other tests.
What results may show
- Low levels can reflect low intake, little sun, absorption problems, kidney or liver problems or medicine effects.
- Very high levels usually come from too many supplements and can be harmful.
What this test may not show
- It does not show why your level is low.
- Reference ranges and cutoffs come from the lab and can differ.
- Supplements and medicines change results.
- Routine screening of everyone is not recommended, so testing is best guided by your situation and your provider.
How to prepare
- No special preparation or fasting is needed.
- Tell your provider about vitamins, supplements and medicines.
- Do not stop a medicine without asking your prescriber.
Where you can get this test
| Option | Price | Includes |
|---|---|---|
| Wellness Panel | $149 | CBC, CMP, lipid panel, vitamin D, A1c, hs-CRP, urinalysis, TSH |
| Comprehensive Health Panel, Women’s | $149 | CBC, CMP, lipid panel, vitamin D, A1c, hs-CRP, urinalysis, TSH |
| Hair Loss Panel | $199 | CBC, ferritin, iron and TIBC, TSH, free T4, vitamin D, total testosterone, DHEA-S |
A doctor’s visit is not required to order. Order online, then visit our Buffalo Grove or Lake Zurich location for the sample. Review results with your own healthcare provider.
Related tests
- Ferritin: Ferritin is a protein that stores iron, so a ferritin test shows roughly how much iron your body has in storage.
- CBC: A CBC counts and sizes your red blood cells, white blood cells and platelets.
- Browse the full Lab Test Library
Frequently asked questions
What does a vitamin D test measure?
25 hydroxy vitamin D, the main marker of your vitamin D status.
Does everyone need a vitamin D test?
No. Routine testing for everyone is not recommended. It is more useful when you have a reason to check.
Do I need to fast?
No special preparation is needed.
Can too much vitamin D be harmful?
Very high levels, usually from supplements, can be harmful. Review results with your provider.
Sources
Medically reviewed by Rodion Levin, FNP-C, Founder and Medical Director. This page is for general education. It does not diagnose a condition or replace advice from your healthcare provider.
