A patient seated in the chair before a blood draw
In person

Vitamin D (25-OH, Total)

Your vitamin D level, as 25-OH vitamin D, from one blood draw.

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  • 2,000+ lab locations. Find one near you
  • Nothing due at the lab. FSA / HSA accepted
  • Ordered by a licensed clinician

At a glance

Collection
Blood draw
A standard blood draw at the lab.
Preparation
None
Nothing to do ahead of time. Water is fine.
Results
2 to 4 days
Typical turnaround after your visit.
Where
2,000+ lab locations
Nationwide, with nothing due at the lab.

About this test

Vitamin D helps your body absorb calcium and keep bones strong. Your skin makes it from sunlight and you get it from food, then the liver turns it into 25-OH vitamin D, the form this test measures. It reflects sun and diet over time. Fasting is preferred but not required.

For adults 18 and older. Test availability varies by lab location.

Who should take this test?

This test is often used by adults with little time outdoors or bone health questions, though low vitamin D often causes no symptoms. Commonly related symptoms include:

Body

  • Tiredness
  • Muscle weakness

Joints

  • Bone aches

Lifestyle

  • Little time outdoors

Ask about this test

Not sure this is the right test?

AI-generated. For information only, not medical advice. Call 911 for an emergency.

What does this test measure?

Your result shows your vitamin D level, which a healthcare provider can read with your health history, diet, time in the sun, and other results such as calcium.

25-hydroxyvitamin D
25-hydroxyvitamin D is the main form of vitamin D circulating in your blood and the usual way vitamin D levels are measured. Your skin makes vitamin D in sunlight, and it also comes from some foods and supplements. It helps your body absorb calcium and keep bones healthy.
Why it’s measured: A common way to check your vitamin D level, which supports calcium and bone health.

How it works

  1. Step 1

    Order online

    Check out here. A licensed clinician in your state reviews your order and sends it to the lab.

  2. Step 2

    Visit a lab

    Bring a photo ID to any of 2,000+ lab locations. No fasting needed, and nothing is due at the lab.

  3. Step 3

    Get your results

    Results post to your account, usually in 2 to 4 days, each number next to the lab’s reference range.

Find a lab near you

Choose from 2,000+ lab locations nationwide. Your order works at any of them.

What your results tell you

Vitamin D is reported in nanograms per milliliter (ng/mL) and compared with the lab’s reference range. Medical groups use different cutoffs.

  • Your number next to the lab’s reference range
  • Explained in plain language
  • A licensed clinician reviews your order and, if appropriate, orders the test.
  • A lab report you can download and share

A healthcare provider reads your vitamin D result with your health history and decides whether any follow-up makes sense for you.

Clinical-grade testing, from the comfort of home.

From the lab to your report, every step of our process meets the gold standard in medical testing.

  • CLIA-certified labs

    Every lab we partner with is certified under the Clinical Laboratory Improvement Amendments, meeting both state and federal standards with regular independent inspections.

  • We protect your health data

    We protect your health data with encryption and do not sell it. Some results must be reported to public health authorities by law. See our Privacy Notice.

  • Rigorous quality assurance

    All partner labs run regular internal quality checks, participate in proficiency testing, and comply with federal and state lab regulations.

  • Clinician-reviewed reports

    Results are reviewed by an independent, licensed clinician.

Questions

Common questions.

Anything else, our care team answers by phone, text, or email.

Your body turns vitamin D from sunlight and food into 25-⁠OH vitamin D in the liver. This form circulates in the blood and reflects your vitamin D over recent weeks to months, which makes it a standard measure of vitamin D status.

Vitamin D can be lower with little time in the sun, a diet low in vitamin D, trouble absorbing nutrients, or liver problems that affect how the body processes it. Levels are often lower in the winter months.

A healthcare provider can help work out what may be behind your result.

Medical groups do not all agree on the exact level that counts as low, and the right target can depend on your health. Your result is compared with the lab’s reference range, and a healthcare provider can explain what it means for you.

A vitamin D level cannot explain tiredness, aches, or low mood on its own, since these have many causes. The lab also notes that this test is a less useful guide to vitamin D activity in people with kidney disease.

Levels above the range can lead to high calcium in the blood, which a healthcare provider can explain.

Lab tests are informational and don’t diagnose conditions on their own. Available to adults 18 and older; test availability varies by lab location. A licensed clinician reviews your order and, if appropriate, orders the test. All testing is performed at CLIA-certified laboratories. Not for emergencies: if you think you may be having a medical emergency, call 911.