Breakthrough Diagnostic Approach to Significantly Improve TB Detection

8 million new cases and 1.25 million deaths reported in 2023. Early detection through effective screening is crucial in identifying TB, preventing its spread, and ultimately working towards its eradication. TB can remain dormant in the body for years without causing symptoms, but it may become active later, particularly in individuals at high risk. Therefore, accurate testing for both active and dormant TB infections is critical for effective screening programs. Current TB testing methods include chest X-rays, sputum cultures, molecular tests, symptom screenings, and skin or blood tests to detect dormant TB infections (TBI). All these methods aim to accurately identify TB with minimal false positives to avoid unnecessary treatments. Now, a new strategy for TB screening addresses the limitations of existing methods, which often fail to detect the disease accurately.

Simultaneously screening for both active and dormant TB infections could significantly reduce infection rates, save lives, and alter the ongoing spread of the disease, according to a new study by researchers at Queen Mary University of London (QMUL, London, UK). The researchers hope that this novel approach, detailed in the European Respiratory Journal, will influence global health organizations and policymakers in defining the most effective screening strategies for TB. In the study, the research team evaluated the effectiveness of combining commonly used TB tests. Their study reviewed data from 437 original studies and published systematic reviews involving 13 different TB tests. The collected data were used to assess the accuracy of these screening tests in both detecting TB and minimizing false positives.

Unlike previous studies, the researchers found that incorporating some immunological tests for dormant TB infection (TBI tests) improved the screening process. These tests could enhance early diagnosis, particularly for harder-to-detect forms of TB, including extrapulmonary TB (which affects parts of the body outside the lungs) and TB in children. This innovative approach challenges traditional TB testing protocols, which generally reserve TBI tests solely for diagnosing dormant TB. Crucially, combining diagnostic tests for both active and dormant TB allows for the detection of both forms of the disease at the same time. This opportunity for enhanced detection across large populations is particularly valuable to policymakers and public health organizations such as the World Health Organization (WHO) and the European Centre for Disease Prevention and Control.

"Global TB control requires early identification and treatment of TB in risk groups,” said Dr. Dominik Zenner, Clinical Reader in Infectious Disease Epidemiology at Queen Mary who led the research team. “Our novel screening algorithms show that screening for active and dormant TB can be done simultaneously with high accuracy for migrants from countries where TB is common to improve individual and population benefits.”