747. Diagnostic Performance of Bronchoalveolar Lavage Fluid Galactomannan Assay in Patients with Negative Serum Galactomannan Assay Suspected with Invasive Pulmonary Aspergillosis

Abstract

BackgroundThere are limited data in real clinical practice on the diagnostic value of BAL (bronchoalveolar lavage) fluid galactomannan (GM) assay in patients with suspected invasive pulmonary aspergillosis (IPA) who had negative serum GM results.MethodsThis study was performed at Asan Medical Center, a 2700 bed tertiary-care hospital in Seoul, South Korea between May 2008 and April 2019. All patients with suspected IPA whose serum GM assays revealed negative results and sequentially underwent BAL were enrolled in this study. Patients were classified as proven, probable, possible or not IPA by the revised 2019 EORTC/MSG definition.ResultsA total of 341 patients with suspected IPA including 4 proven IPA, 38 probable IPA, 107 possible IPA, and 192 not IPA were enrolled. Of these 341 patients, 107 (31%) with possible IPA were excluded from the final analysis. Of 42 patients with proven or probable IPA who had initial negative serum GM results, 24 (57%) revealed positive BAL GM results (n=24) or BAL fungal culture (n=8). Among the remaining 18 (43%), 2 (5%) were diagnosed as proven IPA by the histopathologic exam from transbronchial lung biopsy, 6 (14%) as probable IPA by subsequent sputum fungal culture, and 10 (24%) as probable IPA by repeated serum GM assay after BAL. Of 192 patients with not IPA, 14 (7%) revealed positive BAL GM results (n=14) or BAL fungal culture (n=8). The diagnostic performance of various tests is shown in Table 1.Table 1. Diagnostic performance of various diagnostic tests in patients with suspected IPA who had negative serum GM results ConclusionSequential BAL in patients with suspected IPA who had initial negative serum GM results provided additional diagnostic yield in about half of patients.Disclosures All Authors: No reported disclosures