Quest Says Nearly 10% Of Its Vitamin D Tests Were Inaccurate

Last October, Quest Diagnostics contacted “thousands of doctors” around the country to notify them that one or more of their patients might have received “questionable” results on vitamin D tests performed over the past two years. It’s offering free retests to anyone who was affected.

The errors came about when Quest switched from an FDA-approved test to “a new test of its own design,” reports the New York Times.

So what does it mean to have an incorrect vitamin D analysis?

An erroneously high result may mean patients will not take vitamin D supplements when perhaps they should, doctors said. And an erroneously low test result might lead in rare instances to a toxic overdose of vitamin D. When the Quest tests have been inaccurate, the reading has typically been too high, although not in all cases.

There’s at least one case, reported in the Times article, of a patient who subsequently tested positive for a “toxic level” of vitamin D after his Quest result said he had a deficiency.

Dr. Salameh, a medical director for Quest, says the mass spectrometers Quest uses weren’t calibrated properly, and that 4 of the 7 labs didn’t always follow proper procedure. He also notes, however, that Quest erred on the side of caution by contacting anyone with even the slightest chance of a mistaken test, and that “We are kind of being penalized for going the extra mile.” Actually, we think Quest did the right thing by being overcautious, and Dr. Salameh’s whiny complaint is why you use a spokesperson to speak on behalf of your company.

“Lab Acknowledges Problem With Vitamin D Test” [New York Times]
(Photo: R’eyes)