Genomic test can distinguish between bacterial and viral infections

A blood test developed by Duke Medicine researchers was more than 90 percent accurate when distinguishing between viral and bacterial respiratory infections, according to a study published on Wednesday in Science Translational Medicine.

The study tested the assay in a real-world setting among 102 people arriving at a hospital's emergency department with fever. The test found that 28 people had a viral infection, 39 had a bacterial infection and 35 were healthy controls. The assay provided positive identifications in 89 percent of the cases and correctly ruled out the negative cases 94 percent of the time.

The researchers said the assay could help patients to get faster diagnoses and treatments while reducing the unnecessary use of antibiotics that don't work on viral infections.

"In instances such as pandemic flu or the coronavirus that has erupted in the Middle East, it's extremely important to diagnose a viral illness far more accurately and speedier than can be done using traditional diagnostics," Geoffrey Ginsburg, the co-senior author of the study, said. "Current tests require knowledge of the pathogen to confirm infection, because they are strain-specific. But our test could be used right away when a new, unknown pathogen emerges."

Because the test does not rely on evidence of the pathogen in the bloodstream, the new assay could be used to detect unknown emerging diseases, including possible bioterrorism threats.

"This is important not only in viral pandemics where infection may be caused by unknown viruses but also in routine care where the decision to treat or not with antibiotics is paramount," Aimee K. Zaas, the lead author of the study, said.

The authors said bacterial resistance is a growing threat around the world, often driven by the overuse of antibiotics. By accurately identifying viral infections, the test could reduce the indiscriminate use of antibiotics and the development of resistant pathogens.

"We were very pleased that the assay could pick out those with viral infection with a high degree of accuracy," Zaas said. "This is perhaps the most important aspect of this effort - the accuracy of the new test in a real-world setting. It is a major step forward in the test becoming a useful diagnostic to help physicians and patients."