The Role of Bronchoalveolar Lavage Galactomannan in the Diagnosis of Pediatric Invasive Aspergillosis

Background: Molecular biomarkers such as the galactomannan assay are of increasing interest in clinical settings for diagnosis of invasive aspergillosis (IA). The use of bronchoalveolar lavage galactomannan (BAL GM) is being validated in adult populations, but has not been systematically evaluated in pediatric patients. Methods: A retrospective analysis was performed of patients for whom GM assays from BAL were submitted between November 1, 2006 and November14, 2007 at Childrens Hospital Los Angeles. Medical charts were reviewed and patients were categorized as having no, possible, probable, and proven IA, per established definitions. Results: Of 85 pediatric patients who had a BAL GM submitted during the study, 59 were immunocompromised. Three patients were identified as having proven IA, 6 had probable IA, 37 had possible IA, and 39 had no evidence of IA; 38 had a concurrent serum GM performed. A positive, linear correlation was established between BAL and serum GM, using OD index values (rho = 0.48, P = 0.002). Among immunocompromised patients, receiver operating characteristic curves demonstrated an optimal BAL GM OD cut-off value of 0.87, that yielded a sensitivity for probable/proven IA of 78% and a specificity of 100%. At 0.87, the positive and negative predictive values among immunocompromised patients were 58% and 96%, respectively. Conclusions: We found a correlation between BAL GM values and a diagnosis of IA. We also noted a linear relationship between serum and BAL GM values. Receiver operating characteristic curves obtained from our pediatric data validate the current cut off for serum and suggest a possible cut off for BAL specimens.