OpiniãoThis section briefly describes some of the main terms that are used in this module and elsewhere.
Bacteriologically confirmed: when a biological specimen is positive by smear microscopy, culture or a rapid diagnostic test for TB recommended by WHO.
Clinically diagnosed: when a person who does not fulfil the criteria for bacteriological confirmation has been diagnosed with TB disease by a medical practitioner who has decided to give the person a full course of TB treatment.
Drug-resistant TB (DR-TB): TB disease caused by a strain of Mycobacterium tuberculosis complex that is resistant to any TB medicines.
Drug susceptibility testing (DST): in vitro testing using either molecular or genotypic techniques to detect resistance-conferring mutations, or phenotypic methods to determine susceptibility to a medicine.
Extensive (or advanced) pulmonary TB disease: the presence of bilateral cavitary disease or extensive parenchymal damage on chest radiography. In children aged below 15 years, advanced disease is usually defined by the presence of cavities or bilateral disease on chest radiography.
Extensively drug-resistant TB (XDR-TB): TB disease caused by a strain of M. tuberculosis complex that is resistant to rifampicin (and may also be resistant to isoniazid), and that is also resistant to at least one fluoroquinolone (levofloxacin or moxifloxacin) and to at least one other “Group A” drug (bedaquiline or linezolid).
MDR/RR-TB: refers to either multidrug-resistant TB (MDR-TB) or rifampicin-resistant TB (RR-TB).
Multidrug-resistant TB (MDR-TB): TB disease caused by a strain of M. tuberculosis complex that is resistant to rifampicin and isoniazid.
New case: a person with TB disease who has never been treated for TB or has only previously ever taken TB drugs for less than 1 month.
Operational research or implementation research: “the use of systematic research techniques for programme decision-making to achieve a specific outcome” (5). In the context of this document, these terms are also applied to research that aims to develop the critical evidence base that informs the effective, sustained and embedded adoption of interventions within a health system, to improve health or patient outcomes. Such research deals with the knowledge gap between efficacy, effectiveness and current practice to produce the greatest gains in disease control (6). Operational research also provides decision-makers with information to enable them to improve the performance of their health programmes (7).
Pre-extensively drug-resistant TB (pre-XDR-TB): TB disease caused by a strain of M. tuberculosis complex that is resistant to rifampicin (and may also be resistant to isoniazid), and that is also resistant to at least one fluoroquinolone (either levofloxacin or moxifloxacin).
Rifampicin-resistant TB (RR-TB): TB disease caused by a strain of M. tuberculosis complex that is resistant to rifampicin. These strains may be susceptible or resistant to isoniazid (i.e. MDR-TB), or resistant to other first-line or second-line TB medicines.
Rifampicin-susceptible, isoniazid-resistant TB (Hr-TB): TB disease caused by a strain of M. tuberculosis complex that is resistant to isoniazid but susceptible to rifampicin.
Serious adverse event: an adverse event that leads to death or a life-threatening experience, to hospitalization or prolongation of hospitalization, to persistent or significant disability, or to a congenital anomaly. Adverse events that do not immediately result in one of these outcomes but that require an intervention to prevent such an outcome from happening are included. Serious adverse events may require a drastic intervention, such as termination of the drug suspected of having caused the event.
Severe extrapulmonary TB: presence of miliary TB, TB meningitis, osteoarticular TB or pericardial TB. In children aged below 15 years, extrapulmonary forms of disease other than lymphadenopathy (peripheral nodes or isolated mediastinal mass without compression) are considered severe.
TB case: the occurrence of TB disease in a person.
TB disease: a disease in humans caused by the M. tuberculosis complex, which comprises eight distinct but closely related organisms – M. bovis, M. caprae, M. africanum, M. microti, M. pinnipedii, M. mungi, M. orygis and M. canetti. The most common and important agent of human disease is M. tuberculosis.
TB patient: a person who is in care for TB disease.