Rapid communication on systematic screening for tuberculosis
Overview
Improved TB screening using new tools could help bridge the gap between global TB incidence and the number of TB patients notified by countries. For this reason the World Health Organization (WHO) is in the process of updating its guidelines on the systematic screening of TB disease.
WHO is releasing this Rapid Communication to help national TB programmes and other stakeholders prepare for the changes that will be introduced with the new guidelines in early 2021. The main updates, based on the review of the latest available evidence, are as follows:
· Community-wide systematic screening using a sensitive tool such as CXR followed by an accurate diagnostic test may be used in settings with TB prevalence even lower than 1% - the threshold proposed in the 2013 guidance - based on evidence of public health benefit at such levels.
· CAD may be used as an alternative to human reader interpretation of plain digital CXR for screening and triage for TB. Its use should be limited to the interpretation of plain CXR for pulmonary TB in individuals aged 15 years or more.
· mWRDs may be used for TB screening to improve the accuracy of symptom screening in high risk populations.
· When scaling up CXR and innovations like CAD, CRP and mWRD for screening, due consideration should be given not to create inequities. mWRD needs to be prioritized for use for diagnostic testing of people with presumptive TB. Implementation of CAD will require thorough consideration of infrastructure requirements including digital radiography equipment, computer availability, internet access, as well as the costs for licence and use of different CAD products.
· In people living with HIV:
o Screening with CXR improves the sensitivity of the WHO four-symptom screen (cough, fever, weight loss or night sweats) in detecting TB, including in people who attend HIV care services for ART.
o CRP may be used for TB screening over and above the WHO four-symptom screen in all people living with HIV in high TB-burden settings.
o mWRDs may be used to screen for TB in all people living with HIV as in other high-risk populations in high TB-burden settings. They offer a distinct opportunity to improve timely diagnosis and treatment in hospitalized patients with HIV in medical wards in high TB-burden setting.
