Correction: Occupational Screening for Tuberculosis and the Use of a Borderline Zone for Interpretation of the IGRA in German Healthcare Workers

Performance of Current Diagnostic Tools in Detecting Latent Tuberculosis Among Healthcare Workers: A Systematic Review

Testing for latent tuberculosis infection is essential for diagnosing Mycobacterium tuberculosis infections in asymptomatic individuals. Preventing the transition of latent to active tuberculosis is imperative, especially in high-risk populations such as healthcare workers. Interferon-gamma release assays (IGRAs) and the Mantoux/tuberculin skin test (TST) are two examples of diagnostic instruments utilized for detection. Systematic evaluations of the characteristics of widely available tests are very helpful for diagnosticians because these tests might not be easily accessible in situations with limited resources. This systematic review aims to evaluate and compare the diagnostic accuracy of tests for latent tuberculosis infection in healthcare workers. The review, conducted from 2013 to 2024, aimed to identify studies on "Latent Tuberculosis," "Healthcare workers," "Diagnostic modalities," "TST," "Interferon-gamma release assays," and "IGRA." The review followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines and developed a data extraction toolkit. Three authors independently reviewed the literature, ensuring uniformity. Discrepancies were resolved through discussions and mediation until a consensus was reached. Statistical significance was defined as a p-value of 0.05 or lower. The review provides valuable insights into the diagnostic accuracy of these tests, particularly in high-risk populations. The TST had a sensitivity of 76.5% (confidence interval (CI) = 61.5-91.5%) and specificity of 77.2% (CI = 65-85%). Its positive predictive value (PPV) was 54.8% (CI = 45-65%), and the negative predictive value (NPV) was 88.5% (CI = 85-92%), with an odds ratio of 63.6 and an area under the curve (AUC) of 0.72. QuantiFERON-TB Gold In-Tube (QFT-GIT) showed a sensitivity of 68.35% (CI = 67.15-70.55%) and a specificity of 82.32% (CI = 72.32-97.47%). Its PPV was 56% (CI = 54-92%), and NPV was 92.7% (CI = 89-96%), with an odds ratio of 357.9 and an AUC of 0.767. QuantiFERON-TB Gold Plus (QFT-Plus) had a sensitivity of 85% (CI = 78.9-91.1%) and a specificity of 73.52% (CI = 35.71-93.75%). Its PPV was 59.2% (CI = 39.3-78.2%), and NPV was 95% (CI = 91.2-98%), with an odds ratio of 125.39 and an AUC of 0.89. T-SPOT.TB showed a sensitivity of 92% (CI = 87-97%) and a specificity of 95.7% (CI = 94-98%). Its PPV was 86.8% (CI = 85-95.8%), and NPV was 95.8% (CI = 92.5-96.7%), with an odds ratio of 1.03 and an AUC of 0.7. CLIA-IGRA had a sensitivity of 100% (CI = 99.9-100%) and a specificity of 95.57% (CI = 95.57-100%). Its PPV was 96.8% (CI = 96.8-100%), and NPV was 99.8% (CI = 99.8-100%), with an odds ratio of 1509 and an AUC of 0.97. HBHA-induced IGRA showed a sensitivity of 86.4% (CI = 71.1-97.3%) and a specificity of 82.5% (CI = 66.4-92.6%). Its PPV was 86.8% (CI = 66.7-95.3%), and NPV was 86.4% (CI = 57.8-95.7%), with an odds ratio of 6.18 and an AUC of 0.886. There are specific benefits and drawbacks of each diagnostic test for latent tuberculosis infection. With its exceptional sensitivity and specificity, the CLIA-IGRA test is a top choice for a precise diagnosis of tuberculosis. Practical factors such as availability and cost, however, might prevent its widespread usage. Both the QuantiFERON and TST are still useful tools, especially when used in certain populations or situations when their performance characteristics meet clinical requirements.

Clinical Application of Interferon-γ Release Assays for the Prevention of Tuberculosis in Countries with Low Incidence

Despite global efforts to control tuberculosis (TB) the estimated number of people who developed TB worldwide increased to an all-time record of more than 10 million in 2015. The goal of the World Health Organization (WHO) to reduce the global incidence of TB to less than 100 cases per million by 2035, cannot be reached unless TB prevention is markedly improved. There is a need for an improved vaccine that better protects individuals who are exposed to Mycobacterium tuberculosis from infection and active disease compared to the current M. bovis Bacille Calmette Guérin (BCG) vaccine. In the absence of such a vaccine, prevention relies on infection control measures and preventive chemotherapy for people with latent infection with M. tuberculosis (LTBI), who have the highest risk of progression to active TB. During the past decade, interferon-γ release assays (IGRAs) have increasingly replaced the tuberculin skin test as screening tools for the diagnosis of LTBI in countries with a low incidence of TB. Despite recent WHO guidelines on the management of LTBI, the definition of groups at risk for TB remains controversial, and the role of IGRAs for TB prevention in low-incidence countries remains uncertain. We reviewed the scientific literature and provide recommendations for the use of IGRAs for LTBI diagnosis in low-incidence countries. These recommendations are based on the number of patients needing treatment in order to prevent one case of TB. As the positive predictive value of IGRAs for the development of TB is sub-optimal, research must focus on the identification of alternative biomarkers that offer better predictive ability in order to substantially reduce the number needing treatment while improving the prevention of TB and improving the effectiveness of targeted preventive chemotherapy.