FDA Clears Novel Test for Infectious Gastroenteritis

Megan Brooks

January 15, 2013

The first test that can simultaneously detect 11 common viral, bacterial, and parasitic causes of infectious gastroenteritis from a single patient sample has been cleared for marketing by the US Food and Drug Administration, the agency announced today. The market clearance took place on January 14.

The xTAG Gastrointestinal Pathogen Panel

The xTAG Gastrointestinal Pathogen Panel (GPP), from Luminex Inc, is a multiplexed nucleic acid test that detects the following 7 bacterial causes of gastroenteritis: Campylobacter, Clostridium difficile toxin A/B, Escherichia coli O157, enterotoxigenic E coli (ETEC) LT/ST, Salmonella, Shigella, and Shiga-like toxin producing E coli (STEC) stx 1/stx 2.

The test also detects 2 viruses (norovirus and rotavirus A) and 2 parasites (Cryptosporidium and Giardia), which are other common causes of gastroenteritis.

A Time Saver

"Tests such as the xTAG GPP that can detect viruses, bacteria, and parasites from one sample at the same time can help clinicians more quickly identify and treat what's causing gastroenteritis," Alberto Gutierrez, PhD, director of the Office of In Vitro Diagnostics and Radiology at the FDA's Center for Devices and Radiological Health, said in an agency news release.

"The test could also allow clinicians and public health professionals to more quickly identify and investigate the source of potential gastroenteritis outbreaks," Dr. Gutierrez added.

"The FDA reviewed data for the xTag GPP through the de novo classification process, a regulatory pathway for medical devices that are generally low- to moderate-risk but are not comparable to an already legally marketed device," the agency explained in the release.

"The manufacturer demonstrated the performance of the xTAG GPP by collecting samples from 1,407 patients with suspected infectious gastroenteritis and comparing the xTAG GPP results to individual tests that are known to separately and reliably detect the 11 viruses, bacteria, or parasites associated with the xTAG GPP," the FDA concluded.

The manufacturer also performed the xTAG GPP test on 203 samples from patients with previously confirmed infectious gastroenteritis and on 313 additional specimens from pediatric patients with suspected infectious gastroenteritis, with results comparable to those of the individual tests.

Because of the risk for false-positives, the FDA says all positive results from the xTAG GPP need to be confirmed by additional testing.

According to the Centers for Disease Control and Prevention, between 1999 and 2007, gastroenteritis-associated deaths in the United States increased from nearly 7000 to more than 17,000 annually. Norovirus and C difficile accounted for two thirds of the deaths.