Flu Antigen Tests Reclassified as Class II Devices

Effective this month, the U.S. Food and Drug Administration (FDA) has reclassified antigen-based, rapid influenza virus antigen detection test systems (RIDTs) used directly on clinical specimens from Class I to Class II devices. Further, the FDA is introducing special controls aimed at improving the overall quality of flu testing and reducing the number of misdiagnosed cases.

Given that misdiagnosis of the flu could lead to inappropriate use of antibiotics, failure to use antiviral therapy, and ineffective infection control measures, the FDA believes premarket notification is necessary for these tests "to provide reasonable assurance of safety and effectiveness."

RIDTs are widely used in non-clinical laboratory settings, such as physicians' offices, and evidence from the U.S. Centers for Disease Control and Prevention and the Association of Public Health Laboratories showed the tests were performing poorly in medical practice, resulting in many misdiagnosed cases.

In addition to the reclassification, special controls were established to mitigate health risks. These special controls include new minimum performance criteria; use of FDA-accepted comparator method for establishing the performance (currently, either an FDA-cleared nucleic acid-based test or a correctly performed viral culture method); and annual analytical testing of circulating strains, based on the CDC's annual standardized seasonal influenza virus test panel, as well as emergency analytical reactivity testing of newly emerging strains, when needed.

Additionally, the FDA's final order requires that the results of the last three years of annual analytical reactivity testing be included as part of the device's labeling. The FDA is giving manufacturers one year to come into compliance with the final rule.

Takeaway: Manufacturers have one year to come into compliance with new FDA regulations of RIDTs, including reclassification and implementation of special controls.