. Pepsinogens are inactive precursors of pepsin, proteolytic enzymes present in gastric juice, and are immunologically classified into pepsinogen I (PG I) and pepsinogen II (PG II).
. Pepsinogen I: Secreted by the chief cells and mucous neck cells in the fundus and corpus of the stomach. Low levels of Pepsinogen I may indicate atrophic gastritis, particularly in the corpus of the stomach.
. Pepsinogen II: Secreted by the cells throughout the stomach and proximal duodenum. Elevated levels may suggest gastric inflammation or more extensive gastric mucosal damage.
. Pepsinogen I/II Ratio: This ratio is a marker for atrophic gastritis. A low Pepsinogen I/II ratio (<3) may indicate atrophic gastritis or gastric mucosal atrophy. A high ratio is typically seen in normal gastric function.
. This test is valuable in screening for precancerous gastric conditions, monitoring patients at risk of gastric cancer, and differentiating between types of gastritis.