This test is used to determine if there is a vitamin D deficiency, and to monitor supplementation therapy.
PLEASE NOTE: ALL RESULTS AND INFORMATION PROVIDED BY HEALTH eLABS ARE INTENDED FOR GENERAL HEALTH INFORMATION PURPOSES ONLY. AS SUCH THEY ARE NOT A SUBSTITUTE FOR PROFESSIONAL MEDICAL ADVICE OR A MEDICAL EXAMINATION, AND SHOULD NOT BE USED TO DIAGNOSE, TREAT, PREVENT OR CURE ANY DISEASE, SYNDROME, OR CONDITION WITHOUT THE SUPERVISION OF A LICENSED PHYSICIAN.
PREPARATION: For best results, do not eat or drink anything except water for at least 8 hours before having the test.
What does this test do?
This test measures the quantity of the 25-hydroxy form of vitamin D circulating in the bloodstream.
Why is this important?
Vitamin D is a fat-soluble vitamin that is crucial to maintaining bone health. It occurs in two different forms within the body – vitamin D2 and vitamin D3.
Vitamin D3 is manufactured inside the skin when it is exposed to sunlight. Vitamin D2 is mostly obtained by consuming foods such as oil-rich fish, shiitake mushrooms, and dairy products, orange juice, and grains that have been specially fortified with vitamin D.
Vitamin D deficiency is common throughout the United States, and can be due to the lack of vitamin D present in most foods, the limited sun exposure many Americans receive, and in those with chronic liver or kidney disease. In fact, it is estimated that 2/3 of Americans have insufficient levels of vitamin D, while 1/3 are considered deficient due to extremely low circulating levels.
This is significant because vitamin D helps the intestinal tract to absorb calcium and phosphorus, elements that are essential to building and maintaining strong bones. Vitamin D also plays a role in the neuromuscular and immune systems, as well as many other cellular functions.
This test measures the concentration of vitamin D 25-OH, which is the main form of vitamin D circulating in the bloodstream. It is considered to be the best indicator of vitamin D deficiency, or excess.
What do the results mean?
The vitamin D, 25-OH level listed on the test report comes with a set of reference ranges:
<20 ng/mL Deficiency
20-29 ng/mL Insufficiency
≥30 ng/mL Optimal
Significantly elevated levels of vitamin D, 25-OH can cause hypercalcemia (too much calcium in the bloodstream), a condition that can lead to the formation of kidney stones.
Much more common, however, is vitamin D deficiency that can lead to bone diseases such as rickets, osteomalacia, and osteoporosis, and has also been associated with a range of other conditions such as heart disease, hypertension, diabetes, and cancer.
For those whose test results fall into the “Insufficiency” or “Deficiency” ranges, treatment is available through over-the-counter supplements that contain vitamin D. Of course, all abnormal test results should be followed up with a physician, who will supervise the treatment of any resulting conditions.