Evaluation of the Diagnostic Efficacy of EC-Test for Latent Tuberculosis Infection in Ambulatory People Living with HIV.

BACKGROUND: Latent tuberculosis infection (LTBI) co-infected with human immunodeficiency virus (HIV) is more likely to develop into active tuberculosis (ATB), recombinant Mycobacterium tuberculosis fusion protein (ESAT6/CFP10, EC) Test is a latest developed method for LTBI. Compared with the interferon γ release test assays (IGRAs), the diagnostic performance of EC-Test to LTBI screening in HIV needs to be evaluated.

METHODS: A population-based multicenter prospective study was conducted in Guangxi Province, China. The baseline data was collected and LTBI were measured by QuantiFERON-TB Gold In-Tube (QFT-GIT), EC-Test and T-cell spot of the TB assay (T-SPOT.TB).

RESULTS: A total of 1478 patients were enrolled. when taking T-SPOT.TB as reference, the value of sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and consistency that EC-Test to diagnosis LTBI in HIV is 40.42%, 97.98%, 85.26%, 85.04% and 85.06% respectively; when taking QFT-GIT as reference, the value is 36.00%, 92.57%, 55.10%, 85.09% and 81.13%, respectively. When the CD4+ <200 /μl, the accuracy of EC-Test to T-SPOT.TB and QFT-GIT were 87.12% and 88.89%, respectively; when the 200 ≤ CD4+ ≤ 500 /μl, the accuracy of EC-Test were 86.20% and 83.18%, respectively; when the CD4+ >500/μl, the accuracy of EC-Test were 84.29% and 77.94%, respectively. The incidence of adverse reactions in EC-Test is 34.23% and the serious adverse reactions is 1.15%.

CONCLUSION: EC-Test has good consistency compared with IGRAs in detecting LTBI in HIV no matter in different immunosuppression status or different regions, and the safety of EC-Test is also well, suitable for LTBI screening in HIV in high prevalence settings.