Used in biomedical research to detect and quantify pepsinogen A levels in human serum or plasma samples. Helps assess gastric function and diagnose conditions such as atrophic gastritis, gastric cancer risk, and Helicobacter pylori infection. Commonly used in clinical laboratories and research settings for large-scale screening and monitoring of gastric mucosal health. Provides a sensitive and specific measurement, supporting studies on gastrointestinal diseases and the effects of therapeutic interventions.