A pilot study on nasal wash galactomannan as a surrogate marker for invasive aspergillosis among hematology patients in Thailand

Universal antifungal treatment has been recommended among hematology patients during chemotherapy to prevent invasive aspergillosis (IA) in developed countries, but it remains a significant challenge in resource-limited settings. Identifying at-risk individuals could enhance clinical outcomes. A prospective pilot study was conducted at four Thai tertiary care hospitals from April 2021 to January 2023, aiming to assess the correlation and the potential of nasal wash galactomannan (GM) as an IA predictor in hematology patients. It enrolled all patients with acute myeloid leukemia (AML) requiring induction chemotherapy and those admitted for stem cell transplantation (SCT). Nasal wash fluid samples were collected for galactomannan testing and fungal culture to assess Aspergillus spp. colonization before chemotherapy. The study included 34 AML and SCT patients. Among them, 3/34 tested positive for Aspergillus spp. colonization via nasal wash fungal culture. After six months, 18 (52.9%) patients were diagnosed with IA-15/25 patients with AML and 3/9 SCT recipients. The traditional culture did not predict IA, whereas nasal wash fluid galactomannan cutoff value of 0.46 yielded a sensitivity of 40% and a specificity of 80% for predicting probable and possible IA in patients with AML. However, in the subgroup analysis, the test did not reveal any correlation with IA development. More extensive studies are needed to validate the optimal IA risk prediction strategy.