Performance of serum galactomannan in patients with allergic bronchopulmonary aspergillosis

Few studies have evaluated the performance of serum galactomannan (GM) in patients with allergic bronchopulmonary aspergillosis (ABPA). Herein, we analyse the diagnostic performance of serum GM in ABPA. Consecutive subjects with ABPA and asthma underwent GM estimation using the Platelia assay (Bio-Rad Laboratories). An optical density index of >0.5 was considered positive. One hundred and twenty subjects (70 ABPA, 50 asthma) with a mean (SD) age of 33.0 (13.1) were included in the study. The serum GM antigen was positive in 18 (25.7%) subjects with ABPA compared to 9 (18%) subjects with asthma without ABPA (P=0.32). The sensitivity of the serum GM antigen test in patients with ABPA was 25.7% [95% confidence intervals (CI), 16-38] while the specificity was 82% (95% CI, 69-91). The positive and negative predictive values were 66.7% (95% CI, 46-84%) and 44.1% (95% CI, 34-55), respectively. The area under the ROC curve was 0.54 (95% CI, 0.44-0.64). The sensitivity increased and the specificity decreased with decreasing the serum GM cutoff, and vice versa. The results of this study suggest that serum GM estimation has a limited role in the diagnostic workup of patients with ABPA.