Operational Handbooks

Testing for M. tuberculosis infection using TST or IGRA is useful to support a diagnosis of TB in children with suggestive clinical features who are sputum smear-negative or who cannot produce sputum. A positive test for TB infection indicates prior or current infection with M. tuberculosis and can be particularly useful in the absence of known TB exposure (no positive contact history), as it confirms the child has been infected at some point in time (6, 15).

TST is considered positive (indicating infection with M. tuberculosis) if:

The Xpert MTB/RIF assay is a cartridge-based automated test that uses real-time polymerase chain reaction (PCR) on the GeneXpert® platform to identify M. tuberculosis complex and mutations associated with rifampicin resistance directly from sputum specimens in less than 2 hours (76).

The Xpert MTB/RIF Ultra assay uses the same GeneXpert platform and a new enhanced cartridge developed to improve the sensitivity and reliability of detection of M. tuberculosis complex and rifampicin resistance (76).

Despite challenges with bacteriological confirmation of paucibacillary TB in young children, every effort should be made to establish bacteriological confirmation. In adolescents, who usually have adult-type disease, bacteriological confirmation is common.

Bacteriological confirmation is even more important for children and adolescents who:

The index patient is the initially identified person of any age with new or recurrent TB in a specific household or other comparable setting to which others may have been exposed. An index case is the person on whom a contact investigation is centred but is not necessarily the source case (28).

Young children have a higher risk of developing TB compared with other age groups (4). Risk of TB disease is more pronounced among children and adolescents who:

The management of babies born to women with TB is covered in Section 7.2. The main implications of TPT for the choice of ART in children and adolescents living with HIV are covered in Section 7.1. 

Adherence to any course of treatment is a complex behaviour influenced by many factors, such as personal motivation, beliefs about health, perceived risks and benefits of treatment, comorbidities, competing demands that conflict with taking medicines, the family environment, complexity of the treatment regimen, toxicity of medicines, and trust and relationship with providers. Effective person-centred strategies to promote adherence to TPT may include the following (15):

Children and adolescents on TPT should be reviewed every month for those on a 3-month regimen (e.g. 3HR or 3HP), or every 2 months for those on a 6-month regimen (e.g. 6H) or DR-TB TPT, ideally at a health care facility or by treatment supporters (see Section 6.4) or by using digital tools such as video-supported treatment (69).

IGRA is a whole-blood test that can help to diagnose M. tuberculosis infection. Like TST, it does not differentiate between TB infection and TB disease. IGRA measures the cell-mediated immune response of people with TB infection. T-cells of infected people are sensitized to TB and respond to stimulation with peptides simulating those expressed by TB bacteria by secreting a cytokine called interferon-gamma. IGRA uses peptides from proteins made almost exclusively by M. tuberculosis and other mycobacteria from the M. tuberculosis complex.