Similar to tests run by your healthcare provider, at-home tests check the levels of your vitamin D status biomarker, 25(OH)D, using a blood sample. This requires pricking your finger with a lancet to either fill a vial of blood or collecting a sample on a collection card.
At-home vitamin D tests are typically shipped directly to your home and require you to mail back any samples within a required timeframe for accuracy; some options with vial samples may ask for a same-day return to prevent the blood from clotting.
Sounds easy enough, right? As with any at-home tests, there are pros and cons to testing vitamin D at home versus in a lab or at a doctor’s office.
The first advantage, of course, is the ease. “One of the benefits of at-home testing is that you can take the test when it’s convenient for you,” explains Bonney. “Even if your doctor doesn’t feel it’s medically necessary to have this test done, with an at-home test you can still get the data to supplement as warranted.”
However, it’s important to feel supported in understanding your results, which will vary from company to company. “Like any other lab testing, you’ll get a reference range which doesn’t tell you what optimal levels are,” says Bonney. “These ranges are typically based on what most people are, not what they should be. Doing the test under the guidance of a physician who is focused on making sure you have the right amount of vitamin D is helpful to guide what your dosage of supplementation should be.”
Another consideration is the margin for error. Leaving the test to a professional means you’re not responsible for potential error (i.e., inherent variability) in your results. Some reviewers of at-home tests complain that they were unable to properly collect their sample—although typically companies are good about sending a replacement kit in these instances.