An Observational Cohort Study of Bronchoalveolar Lavage Fluid Galactomannan and <i>Aspergillus</i> Culture Positivity in Patients Requiring Mechanical Ventilation

In this large cohort of critically ill patients, we found a low rate of <i>Aspergillus</i> growth and variable BAL GM elevation. These data suggest that the pretest probability of IPA should be considered low in a general ICU population undergoing BAL evaluation to define the etiology of pneumonia. Elevated BAL GM may not reliably indicate invasive disease, but lack of culture positivity may also miss true infection. Improved scoring systems are needed to enhance pretest probability for diagnostic test stewardship purposes, and tests must be interpreted in their own clinical contexts.