Briefly, pepsin A was detected by incubating with biotin-conjugated polyclonal antibody against porcine pepsin A (Abcam plc) that recognizes human pepsin A. The bound biotin-polyclonal antibody was detected by adding HRP-streptavidin (Abcam plc). The ELISA sensitivity threshold is 0.1 ng/mL compared with the sensitivity threshold of 25 ng/mL for the pepsin A enzymatic assay. In our original publication, we reported a 0% rate of aspiration using the enzymatic assay for pepsin A.1 However, using the more sensitive ELISA on the same airway samples, we have detected a 4% rate of aspiration. The ELISA is more sensitive than the enzymatic assay, likely due to its ability to detect partially degraded pepsin A. Thus, it appears that although the rate of gastric-to-pulmonary aspiration is very low (4% in adults without risk factors for aspiration undergoing elective intubation), it is higher than previously reported using the enzymatic assay for pepsin A.