If you’ve ever been prescribed antibiotics to fight the flu, you’ve experienced first-hand how difficult it is for doctors to distinguish between bacterial infections and viral infections (the flu is the latter). Oftentimes, doctors will prescribe antibiotics just in case it’s a bacterial infection so the patient will recover sooner. Early administration of antibiotics can halt bacterial infections before they spiral out of control, but the practice has led to the overuse of our most precious drugs.

Fortunately, a team of researchers announced yesterday that they may have solved this problem in the form of a blood test. It works by detecting the proteins produced by a patient’s own body in response to infection to quickly determine whether they have been sickened by a bacterial strain or a virus. It returns a result within minutes rather than the hours or days required with typical clinical tests.

Today’s tests aren’t just slow, they also require that the infectious agent has multiplied enough inside the patient’s body that the levels are high enough to be detected, and can misidentify the root cause when a person has concurrent infections. To overcome these hurdles, scientists from Israeli biotech company MeMed looked to the patient’s own body to see which molecules the immune system produces when fighting off different kinds of infections.