evidence: TB screening involves the active identification of people at risk for TB disease. Populations or high-risk groups are screened by assessing symptoms and by using tests, examinations or other procedures that can be applied rapidly. TB screening is sometimes also referred to as "active TB case finding". [...] TB screening is often done during contact investigations in households and community settings, or in clinics, such as HIV clinics, primary health care centres or outpatient departments. Occupational screening might be done in the workplace and screening can also take place in penitentiary or other institutions. Communities at risk can be reached through mobile outreach screening campaigns. [...] Screening aims to identify people who have a higher likelihood of having TB and who need further testing. Screening tests are done as part of algorithms so that people who screen positive receive further diagnostic tests. There are different screening algorithms which depend on the populations being tested (e.g. general population, people living with HIV, people with other risk factors for TB, children) as well as the availability of the tests. The operational handbook that accompanies the guidelines describes several algorithms that reflect the most recent evidence on the performance of these tests and screening algorithms.