The overall scope of this study is to find early tuberculosis (TB) candidate protein biomarkers in different TB study groups vs. controls. The identified biomarkers may become the basis of a rapid diagnostic test able to identify active TB earlier than current practice. In addition, the candidate biomarkers may predict which patients are likely to convert from latent infection to active disease. . This project uses plasma and serum samples collected in a long-standing TB household contact study, the Kawempe Community Health Study, conducted in Kampala, Uganda, a TB endemic area. The study utilizes samples from TB index cases and household contacts that were negative for TB at recruitment. A subset of these contacts developed Mtb infection (i.e., their Tuberculin Skin Test (TST) converted to positive) after 3-6 months, and smaller subset developed active TB after 3 months of follow-up. Control patients were still TST negative at 12 months or 24 months of follow-up. This dataset corresponds to the qualification phase of the study.