OpiniãoContinued monitoring can help programme managers assess the performance of the TB screening components that are within their purview. The following indicators should be considered for each targeted risk group:
1. the number of people eligible for screening;
2. the number of people screened (considering the first screening and second screening separately, if applicable);
3. the proportion of those eligible for screening who were screened;
4. the number of people with presumptive TB who were identified;
5. the number of people undergoing diagnostic investigation;
6. the number of people diagnosed with TB, stratified by type of TB;
7. the proportion of those undergoing diagnostic investigation who have TB;
8. the NNS to detect one person with TB;
9. the proportion of initial defaulters (that is, the number of people diagnosed with TB who do NOT start treatment divided by number of people diagnosed with TB);
10. the treatment success rate and the death rate (using standard cohort analyses).
Additional disaggregation may be done – for example, by age group and sex – but this requires that more detailed data are collected for each individual who is screened.
The uptake of screening in a risk group (the proportion of those eligible for screening who are actually screened) can be assessed only if the size of the target group has been well defined. It is normally possible to obtain the relevant information when screening is conducted within health facilities or closed settings (such as prisons) and through contact investigations. However, it is often difficult to obtain this information from outreach screening programmes – for example, when screening is done in the community – although the estimated population size of a targeted community may be used to obtain a rough estimate of the eligible population.