Comparative evaluation of galactomannan test with bronchoalveolar lavage and serum for the diagnosis of invasive aspergillosis in patients with hematological malignancies.

INTRODUCTION: Invasive pulmonary aspergillosis (IPA) is a major cause of morbidity and mortality in patients with hematological malignancies. In recent years, testing for values of galactomannan (GM) in serum and bronchoalveolar lavage (BAL) fluid has been investigated as a diagnostic test for IPA for such patients, but global experience and consensus on optical density (OD) cutoffs, especially for BAL galactomannan remains lacking.

METHODS: We performed a prospective case-control study to determine an optimal BAL GM OD cutoff for IPA in at-risk patients. Cases were subjects with hematological diagnoses who met established revised definitions for proven or probable IPA established by the European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group (EORTC/MSG, 2008), without the use of BAL GM results. Exclusion criteria included the use of piperacillin/tazobactam and use of antifungals that were active against Aspergillus spp. before bronchoscopy. There were two control groups: patients with hematological diagnoses not meeting definitions for proven or probable IPA and patients with nonhematological diagnoses with no evidence of aspergillosis. Following bronchoscopy and BAL, GM testing was performed using the Platelia Aspergillus seroassay in accordance with the manufacturer's instructions.

RESULTS: There were 51 cases and 20 controls. Cases had higher BAL fluid GM OD indices (ODIs) (mean: 1.27 and range: 0.4-3.78) compared with controls (mean: 0.26 and range: 0.09-0.35). Receiver operating characteristic analysis demonstrated an optimum ODI cutoff of 1.0, with high specificity (100%) and sensitivity (87.5%) for diagnosing IPA.

CONCLUSIONS: Our results support BAL GM testing as a reasonably safe test with higher sensitivity compared to serum GM testing in at-risk patients with hematological diseases. A higher OD cutoff is necessary to avoid overdiagnosis of IPA.