Standard E TB-Feron ELISA and Standard F TB-Feron FIA positivity rates and agreement with QuantiFERON-TB Gold Plus among TB high-risk population in Bandung, Indonesia

Abstract

Tuberculosis (TB) remains a global public health problem. The determination of tuberculosis infection (TBI) using interferon-gamma release assay has now been used widely. We aim to evaluate the positivity rates of Standard E TB-Feron enzyme-linked immunosorbent assay (TB-Feron ELISA) and Standard F TB-Feron fluorescent immunoassay (TB-Feron FIA) and their agreement with QuantiFERON-TB Gold Plus (QFT-Plus) among TB high-risk populations in Bandung City, Indonesia. We conducted a cross-sectional study, including people with a high risk of acquiring TB. We screened subjects for TB symptoms and offered chest X-ray (CXR). Anyone with cough or CXR suggestive of TB was asked to give sputum samples for GeneXpert MTB/RIF Ultra test. The positivity rates and corresponding 95% confidence intervals (CI) were calculated among patients with bacteriologically confirmed TB and among patients with no evidence of TB, no history of TB, and no known contact with TB patient (low risk of TBI). The agreement with QFT-Plus was calculated using Cohen’s κ score. We enrolled 527 subjects, and the proportion of positive results among bacteriologically confirmed TB patients were 8 (53.3%; 95% CI 26.6–78.7), 9 (60.0%, 95% CI 32.3–83.7), and 10 (66.7%, 95% CI 38.4–88.8) by TB-Feron FIA, TB-Feron ELISA and QFT-Plus. The agreement between TB-Feron FIA and QFT-Plus among all subjects was similar to that of TB-Feron ELISA and QFT-Plus (84.1%, κ = 0.66, 95% CI 0.59–0.72). TB-Feron FIA and TB-Feron ELISA showed an acceptable clinical performance compared with QFT-Plus. These tests are useful alternatives for detecting TB infection.