Simple blood test may reduce inappropriate antibiotics

Researchers at Duke Health have developed a blood test to determine if an infection is viral or bacterial, which may help guide treatment and reduce inappropriate antibiotic prescribing.

The test relies on a patient’s gene expression signature in response to certain types of infection. “The body responds in unique and quantifiable ways when exposed to different stresses. These differences can be measured in such a way as to distinguish between bacterial infection, viral infection, and noninfectious illness,” Ephraim L. Tsalik, MD, PhD, assistant professor of medicine at Duke and emergency medicine provider at Durham VA Medical Center, told Infectious Disease News. “This knowledge coupled with technological advances are paving the way for a new type of diagnostic assay, relevant to the clinical setting where they can help curb unnecessary antibiotic use.”

Ephraim L. Tsalik

Tsalik and colleagues conducted an observational study that included 273 patients admitted to the ER with community-onset acute respiratory infection or noninfectious illness and 44 healthy controls. Patients’ peripheral whole blood gene expression changes were measured using microarrays.

Results demonstrated that the blood test was 87% accurate in classifying patients with influenza viruses, rhinoviruses, streptococcal and other common infections — more accurate than procalcitonin (78%; P < .03), a widely used biomarker for bacterial infection. The test also was able to distinguish noninfectious causes of illness.

A similar approach used in a 2013 study by Tsalik and colleagues was 90% accurate in distinguishing viral and bacterial infections in ER patients.

Although this test is highly accurate, results can take up to 10 hours. Researchers are currently working on finding ways to reduce wait time in order to diagnose and begin treatment earlier or withhold antibiotics altogether.

Christopher W. Woods

“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 researcher Christopher W. Woods, MD, professor of medicine and associate director of Duke’s genomic center and an Infectious Disease News Editorial Board member, said in a press 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 treatment in the future.” – by Taylor Groff

References:

Tsalik EL, et al. Sci Transl Med. 2016;doi:10.1126/scitranslmed.aad6873.

Zaas AK, et al. Sci Transl Med. 2013;doi:10.1126/scitranslmed.3006280.

Disclosure: The researchers report no relevant financial disclosures.