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    Blood Test May Predict When Antibiotics Won't Help

    It's still in development, but doctors' office screening method could curb overprescribing, experts say

    WebMD News from HealthDay

    By Randy Dotinga

    HealthDay Reporter

    WEDNESDAY, Jan. 20, 2016 (HealthDay News) -- Researchers say they're closer to developing a blood test that distinguishes between viral and bacterial respiratory infections. This would help doctors predict when antibiotics will and will not work.

    Such a test, done right in the doctor's office, might also help curb overuse of antibiotics -- a practice that has led to drug-resistant bacteria, experts suggest.

    When diagnosing respiratory infections -- such as colds, pneumonia and bronchitis -- it helps to know whether the illness is caused by a virus or bacteria, explained study lead author Dr. Ephraim Tsalik. He is assistant professor of medicine at Duke University School of Medicine in Durham, N.C.

    "Antibiotics treat bacteria, but they do not treat viruses. That's why distinguishing between these various causes of illness is very important to get the right treatment to the right patient, and to offer a prognosis for how the patient is likely to do," Tsalik said.

    Respiratory infections are one of the most common reasons for doctor visits. And about three-quarters of patients get bacteria-fighting antibiotics even though most have viral infections, Tsalik said. "Viruses, for the most part, get better on their own," he said.

    Patients sometimes demand antibiotics even if the illness appears to be a virus, and doctors sometimes prescribe them in order to be "better safe than sorry," he explained. Both cases can expose patients unnecessarily to potential side effects, Tsalik said.

    Equally concerning is that unnecessary use of antibiotics raises the risk that bacteria will figure out how to resist the medications, Tsalik said. Awareness has grown worldwide in recent years over bacterial germs that are no longer easily killed off with antibiotics.

    A quick and affordable test could provide important information about sick patients, said Dr. Dominik Mertz, an assistant professor of infectious diseases at Canada's McMaster University. Mertz wasn't involved in the new research.

    While the new test isn't ready yet, Mertz said, "it might be a new approach that could eventually get there. The test results could be used to reassure yourself as a physician as well as the patient."

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