New Vitamin D Tests Inaccurate

MAYWOOD, ILIn research presented recently at ENDO 2012, the 94th Annual Meeting and Expo of the Endocrine Society, in Houston, Loyola University Chicago Stritch School of Medicine researchers detailed the inaccuracies of two new vitamin D test kits. Earle W. Holmes, PhD, and his team performed the Abbott Architect and Siemans Centaur2 tests on 163 randomly selected blood samples. The test results were at least 25 percent too high or 25 percent too low in 40 percent of the Abbott Architect specimens and 48 percent of the Siemans Centaur2 specimensthe maximum recommended total allowable error is plus-or-minus 25 percent.

"There has been an exponential increase in the number of vitamin D tests ordered for patients," Holmes said. But our study of two newly approved tests showed they had pretty poor performance. He and his team tested the new kits in both men (median age of 59) and women (median age of 54) in the study and compared the results with findings from LCMS (liquid chromatography/tandem mass spectrometry), a gold standard method shown to provide accurate vitamin D measurements.

The LCMS measurements showed 33 of the 163 specimens had vitamin D deficiency, while the Abbott test showed 45 specimens had vitamin D deficiency and the Siemens test showed 71 subjects had vitamin D deficiency. Holmes explained such inaccuracies could lead to overtreatment of vitamin D deficiency, contributing to misdiagnoses of patients and confounding efforts of physicians, nutritionists and researchers to identify the optimal levels of vitamin D for good health.