Abstract False-positive serum β-D-glucan (BDG) results are a recognized diagnostic challenge in the evaluation of invasive fungal infections, particularly in critically ill patients. The test’s limited specificity in intensive care unit (ICU) settings has been ascribed to various confounding factors, including certain antibiotics, hemodialysis filters, and severe bacterial infections.This case describes a 44-year-old woman with severe Pseudomonas aeruginosa pneumonia, diabetic ketoacidosis, and septic shock, who developed refractory hypoxemia requiring veno-venous extracorporeal membrane oxygenation (VV ECMO). Despite negative blood cultures and radiological workup, serum BDG was positive (130 pg/mL), prompting empiric antifungal therapy. However, no further objective evidence of fungal infection was identified despite a repeated positive BDG level. Subsequent sputum cultures grew Pseudomonas aeruginosa, leading to de-escalation from antifungal to targeted antipseudomonal therapy, with notable clinical improvement. This case highlights the diagnostic limitations of BDG in ICU populations, where false positives are frequently associated with severe Gram-negative infection and other confounders. However, as demonstrated in our case, associations with localized infections may also subscribe to BDG elevation in the absence of invasive fungal disease. Recognizing this potential relationship is essential to avoid unnecessary antifungal exposure, reduce drug-related toxicity, and prevent the emergence of antifungal resistance. Given these limitations, we suggest clinicians should interpret BDG results with caution and in conjunction with the overall clinical picture, microbiological data, and radiologic findings to avoid unnecessary antifungal exposure. This abstract is funded by: None
Simpson et al. (Fri,) studied this question.