Galactomannan detection

Positivity to galactomannan in bronchoalveolar lavage (BAL) and serum galactomannan antigen test were used as a proxy for invasive aspergillosis (IA) diagnosis. Serum specimens from patients admitted to Hematology ward were collected between December 2016 and May 2017 (case period) and between December 2017 and May 2018 (control period). These clinical samples were routinely sent to a microbiological laboratory for galactomannan (GM) detection. The GM test was performed according to the manufacturer’s instructions for the Platelia Aspergillus kit (Bio-Rad Laboratories, CA, USA). The optical density (OD) value for each hole of the plate was read, and the GM detection value in the serum or BALF samples was derived as follows: specimen OD value divided by standard OD value. A serum GM value of 0.5 or higher was considered positive.²⁴ If GM detection was negative in the serum of patient with high suspicious of IA, also the bronchoalveolar lavage (BAL) was collected, and the Galactomannan antigen test was performed. The GM positive tests were correlated with clinical and radiological features for the definitive diagnosis of IA.