Comparison of the QuantiFERON-TB Gold Plus and Standard F TB-Ferron FIA (IFN-gamma), Interferon-gamma Release assays

Abstract

Detection of latent tuberculosis infection (LTBI) is an important step for the reduction of tuberculosis (TB) spreading. Currently, the most popular method of LTBI detection is Interferon-gamma (IFN-γ) release assay (IGRA) by QuantiFERON-TB Gold Plus (QFT-Plus), however, it requires multiple steps of enzyme-linked immunosorbent assay (ELISA). In 2019, a novel technique for IFN-γ detection, the STANDARD F TB-Feron FIA (IFN-gamma), has been developed. This test used the automated analyzer to decrease workload and turnaround time. This study aimed to compare the performance and examine the correlation between IFN-γ quantified by QFT-Plus and Standard F TB-Ferron FIA. One hundred specimens were analyzed using the QFT-Plus and Standard F TB-Ferron FIA. The results showed 74% (20/27) agreement between the positive IFN-γ by QFT-Plus and Standard F TB-Ferron FIA, 92% (58/63) agreement between the negative samples, and 90% (9/10) agreement between the indeterminate results. The total agreement of both methods was 87% with Cohen's kappa values of 0.734 and 13 discordant results. In summary, the Standard F TB-Ferron FIA showed a correlation with QFT-Plus in the IFN-γ assay. Pearson’s correlation coefficient of either TB1 or TB2 antigen of the QFT-Plus and the Standard F TB-Ferron FIA was 0.82. Therefore, to reduce workload, Standard F TB-Ferron FIA could be applied as an alternative test for the detection of LTBI.