Screening

It is recommended that asymptomatic adults at increased risk of infection are screened.[88]​ These include persons born in or former residents of countries with high TB prevalence, current or former residents of high-risk congregate settings, people living with HIV, recent immigrants from moderate- and high-incidence countries, patients starting immunosuppressive medications, intravenous drug users, healthcare workers who serve high-risk populations, and contacts of infectious TB cases. Tuberculin skin testing (TST) and interferon-gamma release assays (IGRAs) are the standard methods for identifying people with latent TB infection (LTBI).

Targeted screening and treatment of LTBI is only one aspect of controlling TB in a community; it is recommended that priority is given to early detection and completion of treatment of active TB cases and investigating close contacts of infectious TB cases.

Screening persons other than those in high-risk populations is not recommended. It places a burden on resources and can give rise to false-positive results (both TST and IGRA).

The World Health Organization (WHO) guidelines on systematic screening for TB outline key populations who should be prioritised for TB screening.[89] Systematic screening is strongly recommended in the following populations:

  • People living with HIV

  • Household contacts and other close contacts of individuals with TB

  • People in prisons and penitentiary institutions

  • Current and former workers in workplaces with silica exposure.

Systematic screening is also conditionally recommended in the following populations:

  • Areas with an estimated TB prevalence of 0.5% or higher

  • Sub-populations with structural risk factors for TB, including urban poor communities, homeless communities, communities in remote or isolated areas, indigenous populations, migrants, refugees, internally displaced persons and other vulnerable or marginalised groups with limited access to health care

  • People with a risk factor for TB who are either seeking health care or who are already in care and TB prevalence is 0.1% or higher

  • People with an untreated fibrotic lesion seen on chest x-ray.

Screening tools recommended by WHO include symptom screen, chest x-ray, molecular rapid diagnostic tests, and C-reactive protein. Computer-aided detection is also recommended in some cases as an alternative to human interpretation of digital chest x-ray for screening and triage for TB.[89]

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