Assessing tuberculosis prevalence through population-based surveys
Overview
Tuberculosis (TB) prevalence surveys are most valuable in areas where notification data obtained through routine surveillance are of unproven accuracy or incomplete, and in areas with an estimated prevalence of bacteriologically confirmed TB of more than 100 per 100 000. To help in assessingtheperformanceofTBcontrolprogrammes,toprovideinformation for planning, and to assess trends of the disease burden over time, data on TB can be collected through standard methods in a well-defined study population. This document gives overall guidance in conducting cross- sectionalsurveysofpulmonaryTBdisease. ItisintendedforTBexpertsand advisers at national and international levels, and investigators involved in prevalence surveys.
In general, the primary objective of TB prevalence surveys is to determine the prevalence of pulmonary TB in the general population aged 15 years and above. Such surveys can also be used to establish the prevalence of different TB risk factors and to study the determinants of TB disease. Objectives involving testing for HIV or TB drug sensitivity are discussed here as well but are not systematically recommended because of ethical, statistical, and logistical limitations. A specific limitation of TB prevalence surveys is their inability to estimate the burden of childhood TB due to the unsuitability of the currently available methods for diagnosing that form of the disease.