P499 A cross-sectional observational to assess the role of Bronchoalveolar lavage fluid galactomannan in the diagnosis of invasive pulmonary aspergillosis in non-neutropenic patients

Abstract

Poster session 3, September 23, 2022, 12:30 PM - 1:30 PMObjective: This study was done to assess the role of Bronchoalveolar lavage fluid (BALF) galactomannan (GM) in the diagnosis of invasive pulmonary aspergillosis (IPA) in non-neutropenic patients and to determine the optimal cut-off value of BALF GM for diagnosing IPA in non-neutropenic hosts.MethodsWe conducted a cross-sectional observational study on 96 non-neutropenic patients of age > 18 years with suspected pulmonary infections of fungal etiology. A detailed history of predisposing conditions was obtained and routine laboratory investigations with chest computerized (CT) tomography were performed. Fiberoptic bronchoscopy under local anesthesia and sedation was done using a video bronchoscope. Bronchoalveolar lavage was done from the segment or lobe of interest instilling 60-100 ml of saline withdrawn under low pressure and the sample was tested for a battery of investigations; fungal KOH smear; fungal culture; GM by Platelia Aspergillus enzyme immunoassay; and others required for diagnosis. A protected brush specimen and transbronchial lung biopsy were done wherever feasible. The yield from the BALF GM assay was compared with diagnosis based on definitions given by EORTC/MSG excluding host factors. Patients were classified into three groups namely non-IPA, probable IPA, and proven IPA. For statistical analysis, probable and proven IPA were taken as one group i.e., the IPA group. Mann-Whitney test and Chi-Square test along with Fisher's exact test were performed for inter-group comparison between quantitative and qualitative variables respectively. The receiver operator characteristic curve was used to establish a cut-off point of BALF GM and Serum GM for predicting IPA. Sensitivity, specificity, PPV, and NPV were calculated. The McNemar test was used for the comparison of sensitivity and specificity. Inter-rater kappa agreement was used to find the strength of agreement of BALF GM, BALF culture, and BALF DM.ResultsOut of 96, 1 was diagnosed with proven IPA, 34 were probable IPA cases and 61 were not IPA cases. Chronic kidney disease (CKD) as a risk factor was more common in IPA cases compared to non-IPA cases (25.7% vs. 8.2%, P-value .019). Chest CT showed cavity in a significant number of IPA patients compared to non-IPA cases (60% vs. 29.5%, P-value .003). BALF direct microscopy, culture, and serum GM had sensitivities < 60% but specificities close to 95%. BALF GM showed promising results with a sensitivity of 88.5% and specificity of 85.7% at cutoff value of 0.8.See Figures below.Conclusions: Our study highlights the magnitude of IPA in non-neutropenic hosts with unconventional risk factors like CKD, diabetes, and the need for increased vigilance for diagnosis of IPA in such patients. We suggest a lower cut-off value of BALF GM against 1 as in EORTC/MSG criteria and consider CKD as one of the risk factors for IPA.