Consolidated Guidelines

CXR is recommended by WHO to be used in parallel with the W4SS where CXR is available to assist in ruling out active TB prior to initiating TPT among people living with HIV who are on ART. The GDG agreed that, due to the increased sensitivity, the evidence supported using CXR in addition to the W4SS as a parallel screening strategy in which a positive or abnormal result on either screen would indicate a referral for diagnostic evaluation.

The 2020 meta-analysis of IPD included 23 studies of 16 269 participants living with HIV, all of which reviewed the accuracy of the W4SS. The studies primarily focused on pulmonary TB disease. The unweighted average TB prevalence among participants within these studies was 9.2%, ranging from 1% to 26%; and 52% of people living with HIV screened positive on the W4SS. The sensitivity of the W4SS among all people living with HIV was 83% (95% CI: 74–89) and specificity was 38% (95% CI: 25–53).

Fig.1 summarizes the potential contribution of TB screening to standard TB care practices based on the above frameworks for TB screening and shows the conceptual framework that guided the 2021 update to the TB screening guidelines.

The production of the WHO consolidated guidelines on tuberculosis. Module 2: screening was coordinated and written by Cecily Miller, with support from Annabel Baddeley, Dennis Falzon and Matteo Zignol, under the overall direction of Tereza Kasaeva, Director of the World Health Organization (WHO) Global Tuberculosis Programme. The WHO Global Tuberculosis Programme gratefully acknowledges the contribution of all experts involved in producing these guidelines¹.

The definitions below apply to terms as used in these guidelines, and they may have different meanings elsewhere.

Active (tuberculosis) case-finding (ACF): Provider-initiated screening and testing in communities by mobile teams, often using mobile X-ray and rapid molecular tests. The term is sometimes used synonymously with “systematic screening”.

People in prisons and other penitentiary institutions are at an increased risk for TB compared with the general population, and they often have limited access to health care services. The estimated incidence of TB among people residing in prisons is 23 times higher than that among the general population (24). Data reviewed for the GDG meeting suggest that screening in prisons may improve early case detection, increase overall case detection and reduce TB prevalence.

Children and adolescents are of particular importance in contact screening, given the high prevalence found in the youngest age groups and the importance of rapid diagnosis and treatment owing to the risk of rapid disease progression in children younger than 5 years(23), as well as the importance of initiating preventive treatment if TB disease has been ruled out (see Section 2.4.2).

Household and close contacts of individuals with TB disease are at high risk of TB infection and developing TB disease. A systematic review conducted for the guideline update found the weighted pooled prevalence of TB disease among all close contacts of TB patients was 3.6% (95% confidence interval [CI]: 3.3–4.0), with a median NNS of 35 (95% CI: 17–65). Systematic screening has been strongly recommended since 2012 for contacts of individuals with TB disease {21}, given the high prevalence of disease in this population.

The evidence reviewed about the performance of symptom screening among children and adolescents younger than 15 years who are close contacts of someone with TB included 4 studies with a total of 2 695 participants (see Web Annex B, Table 17, and Web Annex C, Table 10).