Skip to content

    Women's Health

    Font Size

    Newer Vitamin D Tests Often Inaccurate: Study

    Faster, Less Expensive Tests May Overestimate Vitamin D Deficiency
    WebMD Health News
    Reviewed by Louise Chang, MD

    June 25, 2012 -- Two new lab tests to measure blood levels of vitamin D are inaccurate more than 40% of the time, according to a new study.

    Researchers say newer tests tend to overestimate the number of people who are deficient in vitamin D, a problem that could cause patients to be anxious about their health and may lead to over-treatment.

    The study, which was presented at ENDO 2012, the annual meeting of the endocrine society in Houston, is adding to concerns felt in many laboratories and hospitals around the country that the results of vitamin D tests, which have become some of the most frequently ordered blood tests in medicine, are widely unreliable.

    What's more, experts say, vitamin D testing is often ordered under circumstances where there's little solid scientific evidence to support its use.

    "It's a huge problem," says researcher Earle W. Holmes, PhD, a pathologist at Loyola University Stritch School of Medicine, in Chicago.

    Experts who were not involved in the research agree.

    "The biggest problem is that they're not even consistent," says Ravinder J. Singh, PhD, director of the Mayo Clinic's Endocrinology Laboratory in Rochester, Minn. "At least if they were consistent, you could say, values are half or double, compared to other tests. You can never have confidence" in the results, he tells WebMD.

    The new tests, made by Abbott and Siemens, were approved by the FDA last fall.

    They're part of a wave of faster, less expensive tests designed to help laboratories keep up with a boom in demand for vitamin D testing.

    Abbott took issue with the study results, pointing to a company-funded study that showed their vitamin D test delivered results that are accurate and comparable to a widely used reference method.

    Siemens also defended their test, saying they are reviewing the validity of the study.

    Questions Persist About Vitamin D Testing

    It's not the first time questions have been raised about the accuracy of vitamin D tests, however.

    In 2009, Quest Diagnostics, one of the largest medical laboratories in the U.S., sent letters to thousands of doctors warning them that problems with an in-house test may have resulted in inaccurate results being reported to patients. At the time, industry analysts called it the largest patient recall of a laboratory test in recent memory. The company offered free retesting.

    1 | 2 | 3 | 4

    Today on WebMD

    hands on abdomen
    Test your knowledge.
    womans hand on abdomen
    Are you ready for baby?
    birth control pills
    Learn about your options.
    Is it menopause or something else?
    woman in bathtub
    bp app on smartwatch and phone
    estrogen gene

    Send yourself a link to download the app.

    Loading ...

    Please wait...

    This feature is temporarily unavailable. Please try again later.


    Now check your email account on your mobile phone to download your new app.

    Blood pressure check
    hot water bottle on stomach
    Attractive young woman standing in front of mirror