Galactomannan antigen detection using bronchial wash and bronchoalveolar lavage in patients with hematologic malignancies

Background: The diagnosis of invasive pulmonary aspergillosis is challenging. It is unclear whether galactomannan (GM) results from bronchial wash (BW) and bronchoalveolar lavage (BAL) samples differ in a clinically meaningful way. Results: Ninety-six paired (BAL and BW) samples from 85 patients were included. The average age was 53 years, 61 % of the patients were male, and 74.1 % had an underlying diagnosis of AML/MDS (ALL 7.1 %, other hematologic malignancy 18.8 %). 57 (67.1 %) patients were neutropenic, and 56 (65.9 %) patients were receiving mold-active drugs at least 48 h prior to bronchoscopy. The overall agreement between GM detection from BW and BAL was 63.5 % (K = 0.152; 95 % CI 0.008-0.311) and 73 % (K = 0.149; 95 % CI 0.048-0.348) at cut off = 0.5 and = 1.0, respectively. Among 43 positive samples, using a GM cut-off of 0.5, 39 (90.5 %) were positive in BW samples whereas 12 (29.3 %) were positive in BAL samples. The median level of GM in BW (0.28) samples was significantly higher than in BAL (0.20) samples among 53 samples with negative results (P = 0.001). There was no statistically significant difference in the median GM values between the BW and BAL samples with positive results (P = 0.08). There was no significant difference in GM detection between samples with positive and negative results with regard to antifungal, beta lactam antibacterial treatment or neutropenia (60.5 vs 56.6 %; 53.9 vs 46 %; 65.1 vs 54.7 %, respectively). Conclusion: This retrospective study examining two collection techniques suggests that BW may have higher diagnostic yield compared to bronchoalveolar lavage for GM detection.