PPIB and COVID-19: Lei et al. examined residual serum samples by using a β-d glucan assay and GM in 181 COVID-19 patients who had oxygen saturation <94% or respiratory rates >29 breaths/min, and reported positive results in the β-d glucan assay for 32 (17.7%) of 181 patients and positive results in the GM EIA for 14 (7.7%) of 181 patients sampled (53).