Accuracy of BAL Galactomannan in Diagnosing Invasive Aspergillosis: A Bivariate Metaanalysis and Systematic Review

Background A serum galactomannan (GM) assay has been approved for diagnosing invasive aspergillosis (IA). However, the role of the BAL-GM assay has not been well established. Therefore, we conducted a metaanalysis to determine the overall accuracy of BAL-GM in the diagnosis of IA. Methods After a systematic review of English-language studies, the sensitivity (SEN), specificity (SPE), and positive and negative likelihood ratios (PLR and NLR, respectively) of BAL-GM for the diagnosis of IA were pooled using a bivariate metaanalysis. Hierarchic summary receiver operating characteristic curves were used to summarize overall test performance. Potential between-study heterogeneity was explored by subgroup analyses. We calculated posttest probability to evaluate clinical usefulness. Results Twelve reports, including 13 studies, met our inclusion criteria. The summary estimates of the BAL-GM assay for proven or probable IA were as follows: SEN, 0.90 (95% CI, 0.79-0.96); SPE, 0.94 (95% CI, 0.90-0.96); PLR, 14.87 (95% CI, 8.89-24.90); and NLR, 0.10 (95% CI, 0.04-0.24). The four summary estimates of the BAL-GM assay for proven IA were 0.94 (95% CI, 0.86-0.98), 0.79 (95% CI, 0.68-0.86), 4.41 (95% CI, 2.87-6.77), and 0.07 (95% CI, 0.03-0.09), respectively. Significant heterogeneity was present. Conclusions BAL-GM determination is a sensitive and specific test for the diagnosis of proven and probable IA. The measurement of BAL-GM is thus likely to be a useful tool for diagnosing IA. Further studies focused on the impact of treatment agents are needed.