TB KaSPar
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The cost of screening, especially as an outreach activity, can be high. The opportunity cost must be considered and compared with other means for improving early TB detection, such as improving the patient-initiated pathway to TB diagnosis (see 2.1.1). The efficiency of a screening programme can be increased by collaboration with other health and social programmes.
The epidemiology of TB in each setting and the social and the health-system contexts will inform decisions on a TB screening strategy, including how risk groups are prioritized, which screening approach to choose and whether screening of specific risk groups is feasible. Therefore, before embarking on detailed planning, a baseline assessment of the following features should be undertaken:
Tuberculosis (TB) is a major yet preventable airborne infectious disease. About one fourth of the world’s population is infected with TB bacilli, the vast majority of whom have no disease (1, 2). In 2019, an estimated 10 million new TB cases emerged worldwide, and more than 1.4 million people died of TB, making it the leading single infectious disease cause of death that year (2). Of the estimated 10 million people who fell ill with TB in 2019, TB was not diagnosed in an estimated 2.9 million, and they were not enrolled in quality-assured TB treatment (2).
mWRDs are now also recommended for screening people living with HIV. (See 3.1.4 for a full description of their use in screening). A positive mWRD screen result in a person with HIV must be followed by further diagnostic evaluation to confirm or rule out TB.
CAD technologies for automated reading of digital CXR for TB detection offer a promising solution for high-TB burden countries; however, selecting the appropriate CAD product for a particular setting can be complex. When selecting a CAD product, TB programmes and implementers should consider multiple aspects of the technology and its interface with existing infrastructure, including:
Approaches to screening will depend on each group, and intervention-specific indicators should be developed for each approach. In general, however, the data on indicators shown in Fig. 2.5 should be collected for each targeted risk group, such as all close contacts of TB patients or all people living with HIV in care.
Fig. 2.5 Data to be collected for systematic screening programmes for TB
The choice of screening programme will have implications for the resources required and the potential reach and effectiveness of the programme. The decision on which model to use should be based on determining which approach will be most effective for reaching the targeted risk group with the resources available. The effort and resources required to reach the target population can be limited by screening in locations where people gather for other purposes, such as health centres or workplaces, although not all populations can be reached in this way.
