FDA OKs Rapid Test to Detect TB and Antibiotic Resistance


July 25, 2013

The US Food and Drug Administration (FDA) today approved the first test that detects tuberculosis (TB) bacteria as well as determines whether they are resistant to the antibiotic rifampin.

And if that isn't novel enough, the new test simultaneously answers both questions in about 2 hours. Traditional methods to identify antibiotic-resistant TB usually take 1 to 3 months, according to the FDA.

The molecular test, called the Xpert MTB/RIF Assay (Cepheid), is simpler to perform than previous TB tests, the agency said in a news release.

“Less complex tests such as the Xpert MTB/RIF Assay can be used in more diverse settings,” Alberto Gutierrez, PhD, director of the Office of In Vitro Diagnostics and Radiological Health in the FDA’s Center for Devices and Radiological Health, said in a news release. “The early and rapid detection of rifampin-resistant TB can help curb the spread of drug-resistant TB, a major public health threat.”

A study published in the New England Journal of Medicine in 2010 reported that for patients with a positive tuberculosis culture, a single Xpert MTB/RIF Assay was positive in 551 of 561 patients (98.2%) with a positive smear for tuberculosis, and negative in 124 of 171 patients (72.5%) with a negative smear. Conducting 2 additional tests for TB-positive patients with a negative smear boosted sensitivity to 90.2%.

The test also correctly identified 200 of 205 patients (97.6%) with rifampin-resistant bacteria and 504 of 518 patients (98.1%) with rifampin-sensitive bacteria.

More information about today's approval of the Xpert MTB/RIF Assay is available on the FDA Web site.


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