Evaluating the diagnostic efficacy of metagenomic next-generation sequencing in bronchoalveolar lavage fluid for pulmonary cryptococcosis with different clinical and imaging characteristics.

Objective: This study aimed to explore the diagnostic value of bronchoalveolar lavage fluid metagenomic next-generation sequencing (BALF-mNGS) in patients with pulmonary cryptococcosis (PC) exhibiting different clinical and imaging characteristics, thereby enhancing clinical physicians' understanding and application of BALF-mNGS in diagnosing PC.

Methods: A total of 84 patients with PC and 84 non-cryptococcosis patients admitted to the First Affiliated Hospital of Ningbo University from February 2020 to April 2025 were enrolled in this study. Data on basic demographics, medication history, comorbidities, clinical presentations, laboratory test results, imaging findings, and serological test results were collected. The sensitivity and specificity of BALF-mNGS for diagnosing PC and its diagnostic sensitivity across different clinical features were analyzed.

Results: Among the 84 patients with PC, 46 were males and 38 were females. BALF-mNGS results were positive in 72 cases and negative in 12 cases. All 84 non-cryptococcosis patients tested negative using BALF-mNGS. The sensitivity of BALF-mNGS for detecting PC was 85.71%, whereas the specificity and positive predictive value were both 100.00%. Among the 48 patients presenting with cough or sputum, BALF-mNGS was positive in 45 cases, yielding a sensitivity of 93.33%, significantly higher than that of patients without cough or sputum (P < 0.05). Among the 38 patients with lesions located in the right lung, BALF-mNGS was positive in 36 cases, resulting in a sensitivity of 94.74%, higher than that for patients with lesions in the left lung or both lungs (P < 0.05). Of the 57 patients with multiple lesions, 53 tested positive with BALF-mNGS, resulting in a sensitivity of 92.98%, significantly higher than that of patients with single lesions (P < 0.05).

Conclusions: BALF-mNGS demonstrated high sensitivity for diagnosing PC, particularly in patients presenting with cough or sputum, right lung lesions, or multiple lesions. This serves as a valuable tool for the early diagnosis of PC.