Research on vitamin D and its importance to health has convinced many doctors to order blood tests for this vitamin. It is now one of the most frequently ordered tests in the US. Unfortunately, a new study shows that the current tests are not as accurate as one would like. Investigators at the University of Chicago discovered that 40 percent of the samples tested with Abbott’s vitamin D test and 48 percent of the samples analyzed with Siemens test were off by 25 percent or more.
The samples were compared to readings from an older, standard method of determining vitamin D called liquid chromatography/mass spectrometry. Although 33 of the 163 samples came up as deficient with the old-fashioned analytic technique, the newer kits wrongly identified lots more people as deficient in vitamin D. These false positive results could lead to overtreatment for vitamin D deficiency with high doses of the vitamin.
[Presented at ENDO 2012, the 94th Annual Meeting and Expo in Houston]