An overprescription of antibiotics for diseases that do not call for such treatment has contributed to infections developing antimicrobial resistance. To help address this problem, researchers from Duke University Medical Center developed a simple blood test that determines if a person needs antibiotic treatment of not.

The blood test uses "gene signatures" that show which genes are turned on or off. These patterns indicate if the patient is suffering from a bacterial infection or a viral infection.

"A respiratory infection is one of the most common reasons people come to the doctor," lead study author Dr. Ephraim L. Tsalik said in a news release. "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 75 percent of patients with viral infections end up being prescribed with antibiotics, Tsalik said, and this "excess antibiotic use" has consequential health risks.

For the study, the researchers recruited more than 300 patients with respiratory problems from five hospitals. The gene signatures were found to be 87 percent accurate in identifying if the patients had infections from a flu virus, rhinovirus, Streptococcus bacteria and others. It also correctly determined when there was no infection.

The blood test can help doctors give more precise treatments and lessen the unnecessary use of antibiotics, the researchers concluded.

"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," study author Dr. Christopher W. Woods said in the news release. "We are working to develop a test that could be run in most clinical labs on existing equipment. We believe this could have a real impact on the appropriate use of antibiotics and guide the use of antiviral treatments in the future."

The study was published online Jan. 20 in Science Translational Medicine.