Vitamin D is an unusual vitamin in that your supply of it could either be made by the body or
come from the food you eat. Vitamin D levels were first made a public health concern when
a lack of it was found to cause problems for growing children, namely rickets. Now we know
that low vitamin D levels contribute to everything from severe osteoporosis to increasing
one’s risk of developing the coronavirus from China. But how can you test your vitamin D
Go to the Doctor
You can go to the doctor and have your vitamin D levels tested via a blood test. The doctor
or other healthcare professional will take the blood sample via a vein in your arm. These
tests tend to be the most accurate, but there also the most painful.
Your doctor may arrange a vitamin D test to determine if you’re suffering the adverse
effects of certain medications or suspected of having osteoporosis. On the other hand, you
could have too much vitamin D in your system if you’re taking too many supplements. That
can contribute to calcium accumulation in the blood. That can damage your kidneys and
Have the Test Done at Home
There are several different variations of the home vitamin D test. One variation asks you to
draw a blood sample and send it into a lab. Instead of a needle pushed into your vein, you’re
asked to prick a finger and dab the blood on the card. This approach has several benefits.
You can do it at home on your schedule, and you can do it in private.
Another variation asks you to provide a genetic sample, whether via blood or saliva, so that
they can test your genetic makeup. That test won’t tell you what your vitamin D levels are
that day, but it will say whether your body has a tendency to not fully metabolize vitamin D
or a greater than average requirement for it. You can have additional nutritional profiling
done, such as when they determine you should probably increase your calcium intake.
Have a Physical Exam Done
Vitamin D deficiency can only be diagnosed via physical observation or testing when it is
severe. For example, your dentist may diagnose you with a vitamin D deficiency after seeing
the weakening of your teeth and jaw bone. Your doctor might suspect a vitamin D deficiency
or calcium deficiency is to blame if they see thinning bones in an X-ray or MRI. If the vitamin
D deficiency is suspected from these types of exams, it will probably be confirmed by a
Note that you’re unlikely to get your vitamin D level tested if you’re healthy unless you
specifically ask for it. Yet you may need testing if you have conditions that affect fat
absorption like celiac disease or take medications that interfere in vitamin D activity. The list
of medications that can affect vitamin D production and absorption include glucocorticoids
and some anti-seizure medications.
Tell the doctor about every medicine and supplement you’re taking when arranging a
vitamin D test, because these medications and supplements can throw off the test results.
Or you can have a vitamin D test done at home and make an appointment to discuss the results with your primary care doctor.