Jan
Errors in Vitamin D of Quest Acknowledges
The nation’s largest medical laboratory company provided possibly erroneous results to thousands of people who had their vitamin D levels tested in the last two years, the company has acknowledged.
The company,Quest Diagnostics has already sent letters to thousands of doctors listing the patients who might have received “questionable” test results and is offering free retests. The company said it had fixed the problems.
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.
Quest’s action represents “the largest patient test recall I’m aware of in my 20 years in the business,” said Robert L. Michel, editor of the dark report, a newsletter for pathologists that first reported on Quest’s action.
The incident could raise calls for more regulation of diagnostic testing at a time when diagnostics are playing an increasingly crucial role in guiding medical treatment. Many laboratory tests, including Quest’s vitamin D test, do not require approval from the Food and Drug Administration.
But experts say that so far there is no standardization of the tests, meaning that results can differ considerably from one laboratory to another.
Dr. Binkley said that a few years ago he sent a sample of his blood to six laboratories and got results that ranged from 14 nanograms a milliliter, which would be a deficient level, to 41 nanograms — a level three times as high and considered adequate. While the tests’ consistency has improved since then, there can still be substantial variability, he said.
Yet many experts say that even if the tests were accurate, there would still be uncertainty in how to treat patients. There is considerable debate about how much vitamin D is needed and whether vitamin D supplements even prevent various diseases. Vitamin D is usually made by the body when the skin is exposed to sunlight and is also contained in oily fish and some fortified drinks like milk.
Some doctors said they had switched to other testing laboratories because of Quest’s problems. But Quest, based in Madison, N.J., offers numerous tests, from routine blood work to sophisticated genetic tests. No one type of test represents a large potion of its revenue, which was $5.45 billion for the first nine months of 2008.
The company said the retesting would not have a material effect on its earnings. The company’s stock price rose 80 cents Wednesday to $49.20, approximately in the middle of its 52-week range.
Quest and many other laboratories argue that lab quality is already regulated through Medicare and that having to win approval for each new test will slow innovation and raise costs.
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