planning population-based surveys to estimate the prevalence of tuberculosis (TB) at a national level. TB prevalence surveys yield useful information in areas where notification data obtained through routine surveillance are incomplete, or of unproven accuracy, and in areas with an estimated TB prevalence of more than 100 per 100 000. These surveys are used to evaluate the performance of the TB program, and to assess trends over time. To achieve this objective, data are collected through standards methods in a well-defined study |