Used in biomedical research to quantitatively measure pepsin levels in biological samples such as saliva, urine, or gastric fluid. Helps in diagnosing and monitoring gastroesophageal reflux disease (GERD) and laryngopharyngeal reflux (LPR), especially in cases where traditional methods are inconclusive. Enables researchers to study pepsin's role in inflammation, airway diseases, and reflux-related tissue damage. Widely applied in clinical labs and pharmaceutical studies to evaluate the effectiveness of anti-reflux treatments and to investigate pepsin as a biomarker for reflux conditions.