Vitamin D Deficiency Numbers

by Chad Stone

About Chad Stone

Chad Stone is a medical scientist based in the Pacific Northwest. Since 2003, Dr. Stone has has published high-profile articles on the molecular mechanisms of cardiovascular disease and cancer in journals such as Blood and the Journal of the American Heart Association. Dr. Stone is a specialist in blood biology as well as cancers of breast, colon, kidney and other tissues.


Vitamin D is essential for human health. To ensure that you are getting optimal vitamin D from sun exposure and diet, your doctor might suggest that you get a vitamin D test, which typically measures the amounts of 25-hydroxy vitamin in your blood.

Vitamin D

Vitamin D is produced by cells in your skin when you expose yourself to sunlight. Your body needs vitamin D to properly absorb calcium. Individuals deficient in vitamin D might have poor bone health. A 2008 report in “USA Today” explains that low vitamin D levels are also linked to a number of chronic conditions, such as high blood pressure and cancer. For this reason, doctors have started to keep a close eye on their patients' vitamin D levels. Vitamin D deficiency can occur for several reasons, such as lack of sunlight exposure, poor diet or an inability to absorb vitamin D.

Vitamin D Tests

There are multiple ways to test for vitamin D levels in the blood. Some less-common tests look for the amount of pure vitamin D in your blood or the levels of vitamin D-based hormones. MedlinePlus says the most common and most accurate vitamin D test is the aforementioned 25-hydroxy test, which seeks out a precursor to the active hormonal form of vitamin D that is eventually made in your kidneys. By knowing your 25-hydroxy vitamin D numbers, you can determine whether or not you are making adequate vitamin D from sun exposure or getting enough vitamin D from your diet.

Test Numbers

According to MedlinePlus, the normal range for a 25-hydroxy vitamin D test is between 30 and 74 ng/ml. While numbers in the range at the level of 30 ng/ml do not indicate a true medical deficiency of vitamin D, they might not be optimal, according to the Vitamin D Council. At levels below 40 ng/ml, your body does not store vitamin D. To ensure optimal health, the Vitamin D council advises maintaining a 25-hydroxy vitamin level of at least 50 ng/ml.


The Institute of Medicine recommends that adults get 600 International Units (IU) of vitamin D per day. However, not all researchers agree with this number and the Vitamin D Council recommends a much higher intake of 5,000 IU per day.As little as 10 minutes of exposure to the sun can supply such levels during sunny months. If you are concerned with your vitamin D levels, ask your doctor to perform a 25-hydroxy vitamin D blood test. Home test kits are also available from many drugstores and online retailers. If you are found to be vitamin D-deficient, your doctor will likely recommend that you take a vitamin D supplement and get more sun exposure. If these steps fail to bring up your vitamin D numbers, additional tests and prescription-strength vitamin D supplements might be recommended.

Photo Credits:

This article reflects the views of the writer and does not necessarily reflect the views of Jillian Michaels or