Vitamin D helps your body use calcium, which keeps bones and muscles working. A blood test shows how much you have.
What the test measures
The test measures 25-hydroxyvitamin D in your blood. Your doctor reads it as a number, in ng/mL or nmol/L.
Ranges, as set out by the NIH
- 20 ng/mL (50 nmol/L) or above: adequate for most people.
- Below 12 ng/mL (30 nmol/L): too low.
- Above 50 ng/mL (125 nmol/L): too high.
Your doctor decides what your number means for you.
Who may need it
The NIH lists people who make less vitamin D or absorb less of it:
- People who spend most of the day indoors or keep their skin covered
- Older adults
- People with darker skin
- People with conditions that affect how the gut absorbs fat, such as Crohn's disease or celiac disease
- People with obesity, or who have had gastric bypass surgery
What low vitamin D can feel like
In adults, a long-term shortage can cause bone pain and muscle weakness. These signs have many causes, so a test is the way to know.
Book the test
Send us a message on WhatsApp and a phlebotomist can collect at your door. Ask us how to prepare when you book. Discuss your report with your doctor.
Source: NIH Office of Dietary Supplements, Vitamin D fact sheet for consumers