Comparison of QuantiFERON-TB Gold In-Tube (QFT-GIT) and tuberculin skin test (TST) for diagnosis of latent tuberculosis in haemodialysis (HD) patients: a meta-analysis of κ estimates.

Diagnosis of latent tuberculosis infection (LTBI) is a concern in haemodialysis (HD) patients. Many studies have compared QuantiFERON-TB Gold In-Tube (QFT-GIT) and tuberculin skin test (TST) for detecting LTBI and reported the κ statistic of agreement between QFT-GIT and TST in HD patients. The present study aimed to systematically review this literature and conduct meta-analysis of individual studies that estimated the κ between QFT-GIT with TST among HD patients. All relevant published studies that were available as full-text were obtained by searching Medline (1950), Web of Sciences (1945), Scopus (1973) through May 2016. The κ was re-estimated from the individual studies and pooled using random effect meta-analysis. Subgroup analysis and meta-regression were applied to evaluate the effect of Bacillus Calmette-Guérin (BCG) vaccination, TST cut-off points, quality of studies, sample size and age on variation of κ estimate. Eight studies involving 901 HD patients were included in meta-analysis. The pooled κ estimate was 0·28 (I 2 = 18·4%, P = 0·239, 95% confidence intervals 0·22-0·34). The discordance of TST-/QFT-GIT+ was more than TST+/QFT-GIT-. History of BCG vaccination, TST cut-off points and age are related to variation of κ estimates. TST and QFT-GIT are not comparable in detecting LTBI in HD patients. The higher TST-/QFT-GIT+ ratio compared with TST+/QFT-GIT- ratio, may indicate the superiority of QFT-GIT over TST for detection LTBI in HD patients.

Tuberculin and QuantiFERON-TB-Gold tests for latent tuberculosis: a meta-analysis.

BACKGROUND: Up to now, there has been no universal consensus on the agreement between the tuberculin skin test (TST) and the QuantiFERON-TB-Gold test (QFT) in the detection of latent tuberculosis infection (LTBI) among high-risk populations. AIMS: To estimate the agreement between TST and QFT among health care workers (HCWs). METHODS: A meta-analysis in which all major electronic databases, including Medline, Scopus, Web of Sciences and Ovid, were searched until June 2014. All cross-sectional and cohort studies addressing the agreement between TST and the QFT were included. The extracted data were analysed and the results were reported using random effect models. RESULTS: The overall kappa statistic between TST and the QFT was 0.27 [95% confidence interval (CI) 0.22, 0.32] and the adjusted kappa statistic for prevalence and bias was 0.41 (95% CI 0.32, 0.50). The kappa for subjects with and without bacillus Calmette-Guérin (BCG) vaccination was 0.27 (95% CI 0.18, 0.36) and 0.31 (95% CI 0.15, 0.46) respectively. The figures were 0.30 (95% CI 0.16, 0.43) and 0.82 (95% CI 0.74, 0.90) for prevalence-adjusted and bias-adjusted kappa, respectively. CONCLUSIONS: The overall agreement between TST and QFT in the detection of LTBI among HCWs was poor. After adjusting for the prevalence and bias indices, kappa statistics reached fair agreement. The utility of each of these two tests is dependent on the prevalence and burden of tuberculosis as well as the BCG vaccination status.