Performance of Galactomannan, Aspergillus-PCR, and Metagenomic sequencing for the diagnosis of invasive pulmonary aspergillosis in hematological patients

BACKGROUND/PURPOSE(S): Invasive pulmonary aspergillosis (IPA) is a serious fungal infection, and its diagnosis is diverse, especially in patients with hematological disorders. This study aims to determine the optimal diagnostic strategy for IPA in such patients by comparing various microbiological tests. METHODS: A total of 490 blood and 138 bronchoalveolar lavage fluid (BALF) samples collected from 182 IPA and 407 no-IPA patients (based on EORTC/MSGERC criteria) were retrospectively analyzed by metagenomic next-generation sequencing (mNGS), Aspergillus-PCR, and galactomannan (GM) (enzyme immunoassay [EIA] and lateral flow assay [LFA]). RESULTS: In BALF samples, GM-EIA, GM-LFA, Aspergillus-PCR, and mNGS showed sensitivities of 68.1 %, 53.2 %, 83.0 %, and 59.6 %-all higher than in blood (43.7 %, 34.4 %, 51.7 %, 55.0 %). In blood samples, mNGS had the highest sensitivity (71.9 %) in neutropenic patients, which was further improved when combined with GM-EIA (77.1 %). In non-neutropenic patients, Aspergillus-PCR was the most sensitive assay (47.3 %), with sensitivity improving to 56.4 % when combined with GM-EIA. Blood test sensitivities were lower in patients with prolonged antifungal therapy (≥7 days) vs. <7 days (Aspergillus-PCR: 38.6 % vs. 57.0 %; mNGS: 31.8 % vs. 64.5 %; GM-EIA: 27.3 % vs. 50.5 %; all P < 0.05), with no impact on BALF results. CONCLUSION: BALF is critical for accurate IPA diagnosis, particularly in patients with prior antifungal therapy. BALF Aspergillus-PCR offers optimal sensitivity, while blood-based mNGS and PCR are recommended for neutropenic and non-neutropenic patients, respectively. Combining molecular methods with GM testing enhances diagnostic performances. Tailored strategies are essential to improve early detection and clinical outcomes in high-risk hematologic populations.