Systematic review and meta-analysis of galactomannan antigen testing in serum and bronchoalveolar lavage for the diagnosis of chronic pulmonary aspergillosis: defining a cutoff.

Background: A clear cutoff value of galactomannan (GM) has not been established for chronic pulmonary aspergillosis (CPA) and is frequently extrapolated from invasive pulmonary aspergillosis. We performed a systematic review and meta-analysis to evaluate the diagnostic performance of serum and bronchoalveolar lavage (BAL) GM, and to propose a cutoff. Methods: We extracted from the studies the cutoff of serum or/and BAL GM associated with true positives, false positives, true negatives, and false negatives. We performed a multi-cutoff model and a non-parametric random effect model. We estimated the optimal cutoff and the area under the curve (AUC) for GM in serum and BAL samples. Results: Nine studies from 1999 to 2021 were included. Overall, the optimal cutoff of serum GM was 0.96 with a sensitivity of 0.29 (95%CI: 0.14–0.51); specificity of 0.88 (95%CI: 0.73–0.95); and AUC of 0.529 (with a CI: [0.415–0.682] [0.307–0.713]). The AUC for the non-parametric ROC model was 0.631. For BAL GM the cutoff was 0.67 with a sensitivity of 0.68 (95%CI: 0.51–0.82), specificity of 0.84 (95%CI: 0.70–0.92), and AUC of 0.814 (with a CI: [0.696–0.895] [0.733–0.881]). The AUC for the non-parametric model was 0.789. Conclusion: The diagnosis of CPA requires the assessment of a combination of mycological and serological factors, as no single serum and/or BAL GM antigen test is adequate. BAL GM performed better than serum, with better sensitivity and excellent accuracy. [ABSTRACT FROM AUTHOR]