Diagnostic accuracy of the ESAT6-CFP10 skin test for latent tuberculosis infection among jail detainees

As an alternative to the tuberculin skin test (TST) or QuantiFERON-TB Gold In-Tube (QFT-GIT), ESAT6-CFP10 (EC) skin test is an emerging screening method; however, its value in the diagnosis of latent tuberculosis infection (LTBI) in detainees is still unclear in China. Newly admitted detainees meeting inclusion criteria were enrolled, with demographic/clinical data collected via structured questionnaires. TST, EC skin test, and QFT-GIT screenings were performed, documenting the diameter of skin indurations and/or redness at injection sites and blistering reactions at injection sites. In total, 1,038 detainees were enrolled in this study from October 2022 to October 2023 with 236 LTBI (22.7%). The positive rate of TST, EC skin test, and QFT-GIT was 18.1%, 10.6% and 11.9%. The area under the curve for EC was 0.820, indicating a strong concordance with QFT-GIT (κ = 0.673). Compared with QFT-GIT, the sensitivity of EC was 66.9%, and the specificity was 97.0%. The mean induration diameter or redness of EC was significantly larger than that of TST ( P < 0.001). In the regression model, no history of alcohol consumption (aOR = 0.433, 95% confidence interval [CI]: 0.200, 0.938), no history of surgical trauma (aOR = 0.731, 95% CI: 0.539, 0.991), and no drug use (aOR = 0.473, 95% CI: 0.233, 0.961) was identified as a protective factor for LTBI. The EC demonstrated both high specificity and sensitivity comparable to the QFT-GIT. When screening for LTBI among jail detainees in this setting, particular attention should be given to individuals with a history of alcohol consumption, surgical trauma, and drug use. IMPORTANCE Jail detainees represent a vulnerable population with an elevated risk of tuberculosis. The EC skin test demonstrates promising potential as an alternative to traditional diagnostic methods, such as the TST and QFT-GIT assay, for LTBI screening. Targeted screening strategies can facilitate the early detection, diagnosis, and management of LTBI.