Although those of us involved in research and education about vitamin D are often frustrated by how slowly research findings are accepted, it is satisfying to learn that the medical community is rapidly acknowledging the importance of vitamin D to health. Take for example, the increase in vitamin D testing in the past 10-15 years.

The volume of vitamin D tests given to Medicare patients in the U.S. increased by a factor of 83 between 2000 and 2010, according to a recent publication, Trends in Laboratory Test Volumes for Medicare Part B Reimbursements, 2000-2010.

The study presents “the reimbursement volumes per 10,000 enrollees in Medicare Part B for the most common laboratory tests and test panels from 2000 through 2010. These data, consequently, are derived primarily for testing patients who are 65 years or older.”

Using the number of tests per 10,000 enrollees solves two problems: the number of people enrolled in Medicare Part B increased to 44.0 million in 2010 from 37.4 million in 2000 and the total number of tests per enrollee per year increased to an average of 8.67 from 6.42 in 2000. The report covers the most common laboratory tests and also those that increased or decreased in volume by 50 per cent or more during the period. Figure 1, which is taken from the article, shows the number of tests per 10,000 enrollees in the group of tests having to do with immunology or nutrition. The line that represents vitamin D is that blue one that leaps from near 0 in 2000 to nearly 1,300 in 2010.

Of the 65 laboratory tests with increased reimbursement volumes, sorted by amount of increase, vitamin D was number seven. However, numbers one through six, which were all tests for “monitoring of therapeutic drugs with potential for overuse or abuse” or for determining the use of illicit drugs, started from a much lower level in 2000. Thus, although the volume of these tests increased by a larger percentage than vitamin D tests, these tests are all used less than 400 times per 10,000 enrollees per year (all but one are at 150 or less).

Other tests, though they didn’t have the leap of the vitamin D test during the period, are done in larger volumes than the vitamin D test. For example, the test for creatinine is actually given slightly more than 10,000 times per 10,000 enrollees per year. The test for glucose is given just slightly less than 10,000 times per 10,000 enrollees per year. As the figure shows, in 2010 the vitamin D test was performed about 1,300 times for every 10,000 enrollees, but its trajectory is almost straight up.

The take home message? While we often lament about progress in understanding and recognizing the importance of vitamin D in medicine, relative to other topics in medicine, we’re moving pretty quickly.