Bronchoalveolar Lavage Fluid α Amylase Level a Promising Biomarker of Aspiration Syndrome: A Pilot Study.

BACKGROUND AND OBJECTIVE: Aspiration syndrome is a common respiratory disease in clinical practice. We hypothesized that bronchoalveolar lavage fluid (BALF) α-amylase might be a diagnostic biomarker for aspiration syndrome. METHODS: This pilot, multicenter prospective study reviewed consenting adults who underwent clinically-indicated bronchoscopy at six hospitals. BALF samples were obtained using standardized methods. Amylase levels were measured in clinical biochemical laboratory. Aspiration syndrome was clinically diagnosed based on the Expert Task Force on Diagnosis And Treatment of Aspiration Pneumonia in Adults in China (2022) and the guidelines of the Japanese Respiratory Society. RESULTS: Among 248 participants, 159 met clinical criteria for aspiration. The median level of BALF α-amylase in cases was significantly higher than that in controls (2884.2 IU/L vs 30.0 IU/L, P < 0.001). The optimal cut-off was 179.1 IU/L (sensitivity 87.4%, specificity 93.3%, AUC 0.937, 95% CI 0.905-0.970). Subgroup analysis stratified by sex (male or female) and age (< 60 or ≥ 60 years) showed that the specificity and sensitivity remained above 0.80. CONCLUSION: BALF α-amylase might be a promising biomarker for distinguishing aspiration syndrome.