This observational Mycobacterium tuberculosis (MTB) diagnostics evaluation study is a longitudinal study of pulmonary TB suspects who are undergoing sputum evaluation for pulmonary TB. The sensitivity and specificity of the Xpert MTB/RIF (Mycobacterium tuberculosis/rifampin) assay performed on the first sputum collected for Xpert testing will be compared to gold standard conventional culture methods on two sputum specimens, in HIV-infected and HIV-uninfected participants.

Inclusion Criteria:

• Suspected pulmonary TB (more information on the criterion can be found in the protocol)
• Men and women age equal to or greater than 18 years
• Ability and willingness of candidate or legal guardian/representative to provide informed consent
• Collection of two sputum samples for AFB smear and culture collected within 7 days prior to entry.
• Availability of two samples for Xpert MTB/RIF testing collected within 7 days prior to entry.
• Determination and/or documentation of HIV status
• For HIV-positive candidates, a CD4+ cell count obtained within 45 days prior to study entry or drawn at the time of entry at any laboratory that has a CLIA certification or its equivalent.

Exclusion Criteria:

• Either receipt of ≥48 cumulative hours OR three or more doses of anti-TB treatment within 180 days prior to completion of second sputum collection for Xpert testing
• Receipt of more than 7 cumulative days of antibiotics intended for bacterial treatment that may have anti-tuberculosis activity, within the 14 days prior to first sputum collection
• Active drug or alcohol use or dependence that, in the opinion of the site investigator, would interfere with adherence to study requirements

HIV-1-infected and -uninfected men and women, 18 years and older, pulmonary TB suspects who have either a) smear positive sputum or b) clinical suspicion of pulmonary TB including one or more self-reported symptoms of cough, night sweats, weight loss, or fever. Within the 180 days prior to collection of the initial sputum sample, participants will have received none or fewer than 48 hours of TB treatment and, in those 48 hours, fewer than three doses of TB treatment.