16505 Background: Chest infections constitute 36% of all infections in our acute leukemia patients. Conclusively establishing the diagnosis of invasive fungal aspergillosis (IPA), an important cause pulmonary infiltrates and mortality in high-risk febrile neutropenic patients, however, is difficult. We therefore evaluated the value of ELISA for Galactomannan (Gm) antigen and correlated the results with radiological findings. Methods: Twenty patients with persistent high-risk febrile neutropenia were assessed with chest X-ray, high resolution computed tomography (HRCT) chest and bronchoalveolar lavage (BAL) from the affected segment on day 5 of fever. Microbial cultures of blood, sputum and BAL and Galactomannan estimation in serum and BAL were done. IPA was defined as per the Mycoses Study Group criteria. Sensitivity, specificity and negative and positive predictive value of Galactomannan assay and diagnostic yield of each investigation was determined. Results: Diagnostic yield of CXR was 10%, blood culture, mainly gram negative bacilli, 15%, and BAL 20% (Aspergillus - 10%). Based on microbiology, radiology and cytopathology IPA was diagnosed in 16 cases (proven -1, probable -2, possible -13) and miliary tuberculosis, bacterial pneumonia and nocardiosis constituted the remaining. Nodules and halo sign were the most frequent (60%) CT findings in IPA. Sensitivity, specificity and positive and negative predictive value for serum were 78%, 100%, 100% and 64%, respectively, and for BAL, were 87.5%, 100%, 100% and 75%, respectively. Conclusions: CT-guided BAL and serial serum GM estimations are valuable non-invasive screening tools for IPA in high-risk persistent febrile neutropenic patients. No significant financial relationships to disclose.