This information sheet discusses the Xpert MTB/RIF Assay for diagnosing TB. It explains that the new test is a nucleic acid amplification test that diagnoses TB in less than 2 hours and can also determine resistance to rifampin, one of the drugs used to treat TB. The information sheet describes how the Xpert MTB/RIF assay works, its advantages, how the results should be interpreted, what it means if RIF resistance is detected, not detected, or is indeterminate. Addresses for additional information are provided.