People interested in improving their health often ask, “How much vitamin D should I take?” A common response is “Get your blood tested, and supplement according to the results.” The suggestion is logical. However, many folks do not know that the global medical community has yet to agree to standardization of vitamin D testing. In other words, test results can vary from laboratory to laboratory due to different testing equipment and protocols. Furthermore, the optimal reference range for vitamin D levels continues to be a subject of debate.

As a passionate vitamin D advocate, I attended the 2013 Vitamin D Standardization Program (VDSP) Symposium hosted by the U.S. Department of Commerce’s National Institute of Standards and Technology. The symposium featured scientific presentations and discussions by vitamin D testing experts from Australia, Belgium, Canada, Ireland, the United Kingdom, and the United States.

Standardization of the laboratory measurement of vitamin D status is crucial to improve the detection, evaluation, and treatment of vitamin D deficiency. The agenda included presentations of the initial results from VDSP inter-laboratory comparison and commutability studies. The symposium participants highlighted the need for accuracy and consistency in vitamin D laboratory measurements around the globe to improve clinical research and public health programs.

Although the 2013 VDSP Symposium continued the conversation about the need for international standardization of measuring vitamin D status, much work still needs to be accomplished before international standardization of vitamin D measurement can be established.

Moreover, attaining global (or regional) consensus on the optimal reference range for vitamin D levels would greatly facilitate treatment for vitamin D deficiency. And conquering the pervasive vitamin D deficiency epidemic would greatly enhance the health and quality of life of millions of people.