Background: Aspiration has become an increasingly significant health issue worldwide due to high mortality and morbidity of aspiration-related lung diseases. Aspiration, however, is difficult to diagnose accurately due to lack of effective diagnostic biomarkers.

Aims: To explore the diagnostic value of bronchoalveolar lavage fluid (BALF) amylase levels for aspiration.

Methods: We conducted a multi-center cross-section study in 6 hospitals from January 2018 to December 2022. Participants were classified into two groups: aspiration group and control group. BALF amylase levels were measured by biochemical analyzer in clinical laboratory. The levels of amylase in BALF were compared by the Wilcoxon test.

Results: Of 222 enrolled participants (151 cases and 71 controls) , the mean age was (68.7±13.7) years and (50.8±16.9) years, and there were 109 (72.7%) and 33 (46.5%) males for cases and controls, respectively. The median level of amylase in cases was significantly higher than those without aspiration [6795.6 (IQR, 537.0-8645.3) vs 53.7 (IQR,30.0-55.6) IU/L, P<0.001]. BALF amylase is predictive for diagnosing the patients with aspiration (AUC:0.956) with a high sensitivity (98.6%) and specificity (87.4%). BALF amylase specified at 179.1 IU/L was determined as the optimal threshold for distinguishing aspiration. Subgroup analysis stratified by age and sex showed that the specificity and sensitivity remained above 85.0%.

Conclusions: BALF amylase level shows remarkable diagnostic value (cut-off value: 179.1IU/L) and might be a promising biomarker for distinguishing aspiration.

This work was supported by National Key R&B Program of China (2020YFC2005401).