A febrile neutropenic patient 2 weeks post allogeneic stem cell transplant has progressive bilateral nodular infiltrates on HRCT chest. Serum galactomannan (GM) ELISA index is 0.65 (cut-off 0.5). Repeat serum GM after 2 days is 1.2. What is the most appropriate next step for diagnosis confirmation?
- A Serum beta-D-glucan (BDG) assay as standalone confirmatory test
- B Empirical antifungal therapy without further workup
- C Bronchoscopic BAL for GM, fungal culture and Aspergillus PCR ✓
- D Lumbar puncture for CSF India ink preparation
Explanation
Rising serum GM (two consecutive values ≥0.5) in a haematological malignancy/HSCT patient meets EORTC/MSG probable invasive pulmonary aspergillosis criteria, but bronchoscopic BAL for GM (sensitivity higher than serum GM), fungal culture on Sabouraud's agar or Czapek-Dox, and Aspergillus PCR (now recommended by EORTC 2019 as a mycological criterion) together provide the highest diagnostic yield and allow species identification for azole resistance testing. BAL GM cut-off is ≥1.0 for haematological patients. BDG is non-specific. Empirical treatment without establishing diagnosis risks inadequate azole coverage if resistant Aspergillus.
Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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