The first rapid test for viral meningitis has been cleared for marketing by the Food and Drug Administration.
The Xpert EV test (Cepheid)—which was released in Europe last summer—can help identify viral meningitis within 2.5 hours instead of the current 3–7 days, thus helping physicians to distinguish quickly between the viral and bacterial forms of the infection, according to the FDA.
“Since bacterial meningitis can be deadly within as little as 2 days, patients who have viral meningitis are frequently treated with antibiotics as a safeguard,” said Dr. Daniel G. Schultz, director of the FDA's Center for Devices and Radiological Health, in a written statement. By using the rapid test, physicians can reduce this unnecessary antibiotic treatment, he noted.
The Xpert EV test uses reverse-transcription real-time polymerase chain reaction to detect enterovirus, which is responsible for 85%–95% of viral meningitis, in cerebrospinal fluid (CSF). However, the test should not be used in isolation, Dr. Steven Gutman, director of the FDA's Office of In Vitro Diagnostics, said in an interview. “It is not intended that this test would be the sole determinant. It is an adjunctive test used in conjunction with other factors such as history, physical, and other lab tests.”
Indeed, according to the company, the test is designed to be used in conjunction “with standard CSF tests [such as] bacterial gram stain, bacterial culture, CSF glucose, CSF-blood glucose ratio, CSF protein concentrations, and CSF leukocyte counts.” It “fills a clinical testing void,” because it is a fully automated test, thereby allowing “round-the-clock” testing, Cepheid said a written statement.
In a six-site study conducted by the company that included 255 patient samples, the test had a sensitivity of 96% and a specificity of 97%, Dr. Gutman said.