Diagnostic value of galactomannan in tracheobronchial aspirate for <i>Aspergillus</i> infection in lung transplant recipients (the GALACTBAS study)

= 0.54), and combined testing with concordant results improved accuracy to 99.6%. TBA GM demonstrated higher sensitivity than BALF GM for detecting AI in LTR, while maintaining high specificity. Proximal airway samples could complement BALF in future diagnostic strategies.IMPORTANCEThis study provides evidence that galactomannan antigen testing (GM) in tracheobronchial aspirate (TBA) is a highly sensitive, reliable, and less invasive diagnostic tool for detecting Aspergillus infection in lung transplant recipients under universal antifungal prophylaxis, compared to the current standard bronchoalveolar lavage fluid (BALF) GM. These findings highlight the diagnostic value of proximal airway specimens, consistent with the pathophysiology of post-transplant aspergillosis, which often originates in the bronchial tree and may not be adequately captured by BALF early in the disease course. Importantly, the study shows that combining TBA and BALF GM results yields near-perfect diagnostic accuracy, supporting a complementary diagnostic strategy rather than a replacement approach. Although this is a proof-of-concept study, it fills a critical evidence gap in transplant infectious diseases and lays the groundwork for safer, more accurate, and earlier diagnosis of Aspergillus infection, with potential implications for clinical practice, antifungal stewardship, and future guideline development.