Rapid Research in Diagnostics Development for TB Network (R2D2 Kids) and Assessing Diagnostics At POC for TB in Children (ADAPT for Kids)

Participant eligibility criteria: Participants will include children (age \<15 years) who present to care with: A. 2 or more of the following: * Unexplained cough for any duration * TB contact or tuberculin skin test or interferon gamma release assay positive * Abnormal chest X-ray (any abnormality) OR B. Any one of criteria A AND any one of the following: * Unexplained weight loss OR unexplained failure to thrive OR Severe Acute Malnutrition * Unexplained fever ≥2 weeks * Unexplained lethargy or reduced playfulness ≥2 weeks The study will exclude participants who: 1. Completed preventive or active TB treatment within the past 12 months (to increase TB prevalence and reduce false-positive results, respectively); 2. Have taken any medication with anti-mycobacterial activity for any reason for greater than 3 days at the time of enrollment (to reduce false-negatives); 3. Are unable to return for follow-up visits; or 4. Whose parents/guardians are unwilling to provide informed consent or who are unwilling to provide assent if applicable (age determined by local IRB) Assessment of the usability of novel TB tests: The study will also include health workers at each clinical site who are 1) aged ≥18 years and 2) involved in routine TB testing (collecting specimens for or performing TB tests). Personnel who are unwilling to provide informed consent will be excluded.