Quest Owns Up to Problems with Vitamin D Results
Free Retesting Offered to Patients

In a story that made headlines in the New York Times and other national media, Quest Diagnostics acknowledged in January that questionable vitamin D test results coming out of some of its labs lead the company to offer free retesting to a large group of patients beginning in 2007. Quest began an internal investigation into potential vitamin D testing problems after reviewing its own test data, and discovered trouble with reagent preparation and, in certain cases, a lack of strict adherence to operating procedures for the test, the company said in a written statement to CLN.

“After completing an exhaustive review, we concluded that the vast majority of our historical Vitamin D test results are reliable,” the company said. “We also corrected the issues, and are confident that our test is performing reliably. Physicians and patients should take comfort that the company handled this retesting program in such a forthcoming and prudent manner.”

Quest uses its own LC-MS/MS platform for vitamin D testing, and plans to continue to use this method, both for the retesting program and in the future. According to Quest, the ability of LC-MS/MS to specifically and precisely quantify specific forms of Vitamin D, including D2 and D3, gives Quest’s home-brew test unique advantages over traditional immunoassays.