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Updated: May 25, 2026

Diagnosing Pulmonary Tuberculosis with the Xpert MTB/RIF Test
Published on: April 9, 2012
Integrated detection of multi- and extensively drug-resistant tuberculosis using the nitrate reductase assay
E Ramos1, K Fissette, P de Rijk
1Mycobacteriology Unit, Institute of Tropical Medicine, Antwerp, Belgium.
Abstract:
It currently takes 2-3 months to obtain a diagnosis for multidrug-resistant (MDR-) and extensively drug-resistant tuberculosis (XDR-TB). We evaluated the rapid non-commercial nitrate reductase assay (NRA), which is capable of the simultaneous detection of MDR- and XDR-TB, and compared the results with the proportion method (PM). The sensitivity was respectively 97%, 99%, 100% and 94.6% for rifampicin (RMP), isoniazid (INH), ofloxacin (OFX) and kanamycin (KM). The specificity was respectively 100%, 95%, 95.7% and 99% for RMP, INH, OFX and KM. The turnaround time for NRA was 10-14 days, compared to 4-6 weeks for the PM. Our study showed that NRA provided sensitive and specific detection of resistance to first- and second-line drugs.
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