Inclusion Criteria:  Pediatric Cohort  <8 years of age  Identified with suspected PTB defined as follows:  A child with ≥1 of the following criteria: Persistent unremitting cough (or cough significantly worse than usual in child with chronic lung disease including HIV-related) of >2 weeks duration, unresponsive to a course of appropriate antibiotics (when clinically indicated) Poor growth documented over the preceding 3 months [clear deviation from a previous growth trajectory and/or documented crossing of centile lines in the preceding 3 months and/or; weight-for-age, or weight-for-height Z-score of ≤2 in the absence of information on previous/recent growth trajectory AND not responding to nutritional rehabilitation (or to antiretroviral therapy if HIV-infected)] Persistent unexplained lethargy or reduced playfulness/activity reported by the caregiver. Persistent (>1w) unexplained fever (>38C), reported by a guardian or objectively recorded at least once; In infants 0-60 days, also: unresponsive neonatal pneumonia or unexplained hepatosplenomegaly OR sepsis-like illness (all other more common causes excluded and/or not responding to appropriate therapy/ broad-spectrum antibiotics/antivirals).  OR  2) Any duration of cough/ wheeze/ acute pneumonia with ≥1:  TB exposure. Either: i) Documented/Reported exposure to a known TB source case (regardless of smear status) in previous 12months OR ii) immunological evidence: positive IGRA or positive TST (defined as >5mm in HIV infected or severely malnourished, >10 otherwise) Chest radiograph suggestive of TB.  Adult Cohort (WHO definition of a HIV-positive presumptive TB case)  > 15 years of age Confirmed HIV infection (ELISA or molecular) Presenting at any health facility with any of the following: cough, fever, night sweats or unintentional weight loss (any duration).  Exclusion criteria  Participants will be excluded (both from study groups) if:  Receiving TB treatment for >72 hours in previous 2 weeks History of TB treatment in the last year Refusal to provide consent for study participation or HIV testing when status is unknown Severe illness resulting in unstable condition Absolute contra-indication to any of sampling procedures required by the study (ie: acute severe asthma, pertussis syndrome etc.)