Go to your doctor with a sinus infection and the first thing she’ll likely ask you is how long you’ve been sick. If it’s been less than two weeks, chances are she’ll say you probably have a viral infection and won’t prescribe an antibiotic. If you say it’s been three or four weeks, she’ll probably give you a prescription, assuming viral infections typically resolve in two weeks. But this rule of thumb is more educated guess than science.
In a nice example of precision health, a new blood test being developed at Stanford could indicate whether you have a bacterial infection or a viral infection and tell you and your doctor whether an antibiotic would help.
So if you have a bacterial infection that an antibiotic could cure, you won’t have to wait days or weeks to get treatment. And if you don’t need a prescription, you won’t damage your body’s microbiome with a round of antibiotics you don’t need.
The test, developed by Purvesh Khatri, PhD, assistant professor of medicine, and a team of six other researchers at Stanford, is based on changes in the way human immune cells express their genes.
It seems almost like science fiction, but Khatri’s team has found that cells don’t just respond differently to bacterial infections and viral infections; they also respond differently to different kinds of viral infections, so it’s possible to tell whether someone has a cold versus the flu as much as 24 hours before they even show symptoms.