OpiniãoNote: Unless otherwise specified, the definitions listed below apply to the terms as used in this handbook. They may have different meanings in other contexts.
Active case finding (ACF): is synonymous with systematic screening for tuberculosis (TB) disease, although usually implemented outside a health facility.
Adolescent: is a person aged 10–19 years.
Adult: is a person aged > 19 years.
At-risk group: is any group of people in which the prevalence or incidence of TB is significantly higher than in the general population.
Bacteriologically confirmed TB: refers to TB diagnosed in a biological specimen by smear microscopy, culture or a WHO-approved rapid diagnostic test such as Xpert® MTB/RIF or a urinary lipoarabinomannan assay.
Child: is a person aged < 10 years.
Contact: is any person who has been exposed to a person with TB disease.
Contact investigation: refers to systematic identification of previously undiagnosed TB disease and TB infection (TBI) among the contacts of an index person and/or settings where transmission occurs. Includes clinical evaluation and/or testing and provision of appropriate anti-TB therapy (for people with confirmed TB) or TB preventive treatment (TPT) (for those without TB disease).
Close contact: is a person who is not in the same household but shared an enclosed space, such as at a social gathering, workplace or facility, for extended periods during the day with an index person with TB during the 3 months before commencement of the current TB treatment episode.
Differentiated HIV service delivery mode: is a person-centred approach to simplify the provision of HIV services along the cascade, in ways that both serve the needs of people with HIV better and reduce unnecessary burdens on the health system.
High TB transmission setting: refers to a setting with a high frequency of individuals with undetected or undiagnosed TB disease, or where infectious TB patients are present and there is a high risk of TB transmission. TB patients are most infectious when they are untreated or inadequately treated. Transmission will be increased by aerosol-generating procedures and by the presence of highly susceptible individuals.
Household contact: is a person who shared the same enclosed living space as the index person for one or more nights or for frequent or extended daytime periods during the 3 months before the start of current treatment.
Index person with TB: is the initially identified person of any age with new or recurrent TB in a specific household or other comparable setting in which others may have been exposed. An index person is the one on whom a contact investigation is centred but is not necessarily the source.
Infant: is a child aged < 1 year (12 months).
Latent tuberculosis infection: is a state of persistent immune response to stimulation by Mycobacterium tuberculosis antigens with no evidence of clinically manifest TB disease. Most infected people have no signs or symptoms of TB but are at risk for TB disease. As infection cannot always be considered latent, however, the term “TB infection” is now used. There is no gold standard test for direct identification of M. tuberculosis infection in humans.
People who use drugs: are those who engage in harmful or hazardous use of psychoactive substances, which could negatively affect their health, social life, resources and legal situation.
Programmatic management of TB preventive treatment (PMTPT): refers to all coordinated activities by public and private health caregivers and the community for providing TPT to people who need it.
Skin test: refers to intradermal inoculation of either tuberculin (TST) or M. tuberculosis antigen (TBST) to elicit a response indicative of TBI.
Systematic screening for TB disease: refers to the systematic identification of people at risk of TB disease in a predetermined target group by assessing symptoms and using tests, examinations and other procedures that can be applied rapidly. For those who screen positive, the diagnosis must be established by one or several diagnostic tests and additional clinical assessments, which are together highly accurate. This term is sometimes used interchangeably with active TB case finding. It should be distinguished from testing for TB infection with a TB skin test or interferon-γ release assay.
TB preventive treatment (TPT): is treatment offered to individuals who are considered to be harbouring TBI and to be at risk of developing TB disease in order to reduce that risk. Also referred to as treatment of LTBI or TB infection, or TB preventive therapy.
Tuberculosis (TB): is the disease state due to M. tuberculosis. In this document, it is referred to as “TB disease” in order to distinguish it from “TB infection”. In some sources, it is referred to as active TB.
Tuberculosis infection (TBI): is a state of persistent immune response to stimulation by M. tuberculosis antigens with no clinically manifest TB disease. Most infected people have no signs or symptoms of TB but are at risk of TB disease. TBI was previously referred to as “latent TB infection” or LTBI, but, as infection cannot always be considered latent, the term TBI (TBI) is preferred. There is no gold standard test for direct identification of M. tuberculosis infection in humans.
Underweight: in people ≥ 19 years, usually refers to a body mass index < 18.5 kg/m2; in people aged < 19 years, refers to a weight-for-age < –2 z-scores.