FDA Lowers Nucleic-Acid-Based TB Test Risk Classification

Emma Hitt, PhD

March 19, 2012

March 19, 2012 — The risk classification for nucleic acid–based tests is being downgraded from class 3 (high risk) to class 2 (moderate risk) by the US Food and Drug Administration (FDA), which will allow for easier approval of such tests. Class 3 device classification requires a more rigorous premarketing application and approval process.

"This rule would lower the current risk classification for nucleic acid-based tests allowing manufacturers to utilize the faster, more streamlined clearance pathway for medical devices," the FDA writes in a news release issued March 16.

Nucleic acid–based tuberculosis (TB) tests can detect the presence of TB-derived RNA or DNA in sputum, allowing timely identification of TB disease. In conjunction with the classification downgrade, the FDA issued draft guidance on March 19. The guidance outlines the reclassification of in vitro diagnostic devices for the detection of Mycobacterium tuberculosis complex in respiratory specimens and identifies the risks associated with nucleic acid–based tests. Such risks include false-negative and false-positive results, as well as the risk for TB transmission to healthcare workers who handle specimens for nucleic acid–based tests.

According to the draft guidance, which is available at on the FDA's Web site, test manufacturers "will need to show that its device addresses the issues of safety and effectiveness identified in the guidance, either by meeting the recommendations of the guidance or by some other means that provides equivalent assurances of safety and effectiveness."

The US Centers for Disease Control and Prevention (CDC) "recommends [that] healthcare providers perform nucleic acid testing on at least one sample of mucus coughed up from the lower airways (sputum) from patients with signs and symptoms of TB disease when the test result would alter patient treatment or TB control activities," according to the FDA news release.

"Improving access to promising new TB tests is critical to advancing TB prevention efforts. New tools for diagnosis, and greater emphasis on tools that will help identify drug resistance, are essential for eliminating TB in the United States," said Rear Admiral Kenneth G. Castro, MD, director, Division of Tuberculosis Elimination, CDC, in the FDA news release.

As part of the 510(k) premarket notification of a new device, devices classified as class 2 are also subject to special controls, which may include special labeling, mandatory performance standards, and postmarket surveillance.

Written comments regarding the draft guidance can be submitted to the Division of Dockets Management (HFA-305), Food and Drug Administration, 5630 Fishers Lane, Room 1061, Rockville, Maryland 20852. Comments can also be submitted at http://www.regulations.gov.


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