New test can tell between viral and bacterial respiratory infection

By John Murphy, MDLinx
Published January 22, 2016

Key Takeaways

Researchers reported a gene expression test that will determine, with nearly 90% accuracy, whether a patient’s respiratory infection is caused by a virus or a bacteria, according to a study published online January 20, 2016, in Science Translational Medicine. Clinical use of such a test would lead to more precise treatment and minimize overprescribing of antibiotics, the researchers predicted.

“A respiratory infection is one of the most common reasons people come to the doctor,” said the study’s lead author Ephraim L. Tsalik, MD, PhD, Assistant Professor of Medicine at Duke University School of Medicine, in Durham, NC, and emergency medicine provider at the Durham VA Medical Center.

He added, “We use a lot of information to make a diagnosis, but there’s not an efficient or highly accurate way to determine whether the infection is bacterial or viral. About three-fourths of patients end up on antibiotics to treat a bacterial infection despite the fact that the majority have viral infections.”

In this observational study, the researchers recruited 273 participants with respiratory problems from visits to emergency departments at 5 hospitals, along with 44 healthy control subjects. The researchers used a blood test to identify gene expression classifiers, which distinguish different genes that express whether a patient is responding to a noninfectious illness or to a bacterial or a viral acute respiratory infection.

Test results were 87% accurate in classifying patients with flu viruses, rhinovirus, several strep bacteria, and other common infections, as well as identifying noninfectious respiratory illness.

However, the test’s current technology can take as long as 10 hours to provide results. So, the researchers are now working with developers to create a 1-hour test for use in clinics.

“The ideal scenario, should this test ultimately be approved for broad use, is you would go to the doctor’s office and receive your results by the time you meet with your provider,” said the study’s senior author Christopher W. Woods, MD, MPH, Professor of Medicine and Global Health at Duke University School of Medicine, and Chief of Infectious Diseases at Durham VA Medical Center.

“We are working to develop a test that could be run in most clinical labs on existing equipment,” Dr. Woods added. “We believe this could have a real impact on the appropriate use of antibiotics and guide the use of antiviral treatments in the future.”

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