The End TB Strategy puts renewed emphasis on the need to ensure early and correct diagnosis for all people with tuberculosis (TB). Important progress has been made in improving laboratory services in recent decades. New bacteriological tests for TB diagnosis have become available and their use is now being scaled up. Efforts have been made to ensure that people who seek care and have symptoms consistent with TB are correctly triaged and evaluated for TB. Systematic screening for active TB in high-risk groups is being implemented and scaled up in several places. However, despite these efforts, many people with TB remain undiagnosed or are diagnosed only after long delays.
Chest radiography, or chest X-ray (CXR), is an important tool for triaging and screening for pulmonary TB, and it is also useful to aid diagnosis when pulmonary TB cannot be confirmed bacteriologically. Although recent diagnostic strategies have given specific prominence to bacteriology, CXR can be used for selecting individuals for referral for bacteriological examination, and the role of radiology remains important when bacteriological tests cannot provide a clear answer. Access to high-quality radiography is limited in many settings. Ensuring the wider and quality-assured use of CXR for TB detection in combination with laboratory-based diagnostic tests recommended by the World Health Organization (WHO), can contribute to earlier TB diagnosis and potentially to closing the TB case-detection gap when used as part of algorithms within a framework of health-system and laboratory strengthening.
This document summarizes WHO’s recommendations on using CXR for TB triaging, diagnosis and screening. It also outlines a framework for the strategic planning and use of CXR within national TB programmes (NTP). Moreover, the document provides a brief overview of technical specifications, and quality assurance and safety considerations for CXR. However, because these technical aspects are generic and should be
addressed as part of the general strengthening of radiography and imaging services, this document does not go into technical details. General radiography guidance is provided elsewhere.
The document focuses on CXR, with a major emphasis on detecting pulmonary TB. CXR can be useful for diagnosing other forms of TB (for example, miliary or pericardial TB, or tuberculous effusions) and other imaging techniques are also valuable for TB diagnosis, for example, for extrapulmonary TB, but these topics are not discussed in this document.
The document is mainly intended for NTPs and partners helping with the planning and implementation of national TB care and prevention efforts. It is not intended to be a clinical guide. The recommendations and principles that are summarized in this document need to be adapted to each setting’s TB epidemiology and health-system capacity.