PTX3 and Ito hypomelanosis: For suspected COPD–IPA, prioritize testing BALF GM (optimal ODI ≥ 1.01; sensitivity 68.7%, specificity 91.9%) when bronchoscopic sampling is feasible and safe; otherwise, employ a serum-centered panel comprising GM (optimal ODI ≥ 0.6; 56.5%, 87.7%) with or without PTX3, IL-6, and IL-8.