What Is a Vitamin D (25-Hydroxy) Blood Test? Measures and Costs

This page explains what the test measures and where to buy it for the least money. It does not say what your number means: ranges and units differ by lab, and reading a result is a clinician's job. The live price for every store we track is on our vitamin D marker page, and every plan is ranked on the best blood tests page.

What it measures

Vitamin D reaches the body from sunlight on the skin, from a few foods and from supplements. Before the body can use it, MedlinePlus says, "your liver must change it into another form called 25 hydroxyvitamin D, or 25(OH)D" (MedlinePlus). That circulating form is what the standard test reads. Quest calls 25-hydroxyvitamin D "the most reliable indicator for the overall level of vitamin D in your body" (Quest), and Labcorp's page says its test "evaluates 25-hydroxyvitamin D (25-D): the best measure of how much vitamin D is stored in your body" (Labcorp OnDemand).

Results may come back as one total figure or split into vitamin D2 and D3. MedlinePlus notes that "If you add vitamin D2 and D3 together, you get your total vitamin D" (MedlinePlus). For background on vitamin D itself, where it comes from and what it does, the NIH Office of Dietary Supplements keeps a plain-language consumer fact sheet.

The other vitamin D test

There is a second, different test, for 1,25-dihydroxyvitamin D, the active form. MedlinePlus says "This test isn't usually used to check if you have enough vitamin D" (MedlinePlus); clinicians use it in narrower situations, such as kidney problems or unusual calcium levels. When you shop, check that the test name says 25-hydroxy, 25(OH)D or calcidiol. Every price on this page is for that test.

Who it is for

MedlinePlus is direct that "Routine vitamin D testing is not recommended for everyone" (MedlinePlus). It lists situations where a provider may order one, such as bone conditions, little sun exposure, conditions that affect how nutrients are absorbed, or certain medicines. If you are unsure whether the test is worth buying, your clinician can tell you.

A few practical points:

• It is a standard blood draw at a Quest or Labcorp patient service center.
• Preparation differs by store. MedlinePlus says no special preparation is needed, and Labcorp lists none; Quest's page recommends fasting. Follow the instructions for the test you buy, and tell your clinician about supplements you take.

Why we do not print a range

Labs report vitamin D in different units and use their own cut-offs. MedlinePlus explains that "because labs often use different testing methods, they often use different reference ranges to describe normal results" (MedlinePlus). Use the range on your own report, and ask your clinician what it means for you.

Where to get it and what it costs

The 25-hydroxy test is sold on its own by every lab-test store we track, and it is one of the pricier common single tests. The table below shows each store's single-test price, cheapest first, with the fee that store adds per order, and the memberships whose panels include it:

List prices from each store's own page. Memberships and panels that include it: Function Health, Superpower, Empirical Health, InsideTracker, Mito Health, Lifeforce, Marek Health, Labs by Hims, Maximus, Everlywell, Quest, Labcorp OnDemand, Ulta Lab Tests, SiPhox Health, Rythm Health.

How to pay the least:

• You want vitamin D only: a lab-test store. Add the per-order fee to the test price before comparing; our lab test orders price page includes the fees.
• You want vitamin D with other common tests: put them in one order at one store, so one fee covers them all. Our guide to blood test cost without insurance prices seven common tests together.
• You want a broad yearly panel anyway: most memberships include vitamin D; our biomarker coverage table shows it plan by plan. Superpower starts at $199 a year and Function Health at $365 a year.

Our reviews of Labcorp OnDemand and Quest cover ordering, the draw and how results arrive. Home finger-prick kits also test vitamin D; see Everlywell for one example.

Already have your results?

If you already have a vitamin D result and want help keeping track of it over time, LifeFrom, a sister app from the team behind this site, can keep your results in one place and explain them in plain language (LifeFrom). It is our own sister product, not a lab or a clinician; what a result means for you, and whether to change anything, is a question for your clinician.