A diagnostic test developed by Stanford Medicine scientists can separate bacterial and viral infections with 90% accuracy, the first to meet standards set by the World Health Organization

It is the first diagnostic test to meet (and exceed) the standards proposed by the World Health Organization and the Foundation for Innovative New Diagnostics.

“Antimicrobial resistance is continuously rising, so there has been a lot of effort to reduce inappropriate antibiotic usage,” said Purvesh Khatri, PhD, associate professor of medicine and biomedical data science, and the senior author of the paper. “Accurately diagnosing whether a patient has a bacterial or viral infection is one of the biggest global health challenges.”

Existing methods include growing the pathogen in a petri dish, which takes several days, or polymerase chain reaction (PCR) testing, which requires knowing the specific pathogen to look for.

That’s why in many cases, “Doctors prescribe antibiotics empirically,” Khatri said. “They say, ‘We’re going to give you an antibiotic and if you get better, you had a bacterial infection. If you don’t, you have a viral infection, and we’ll stop the antibiotic.’”