1. To perform upper gastrointestinal endoscopy on the study participants and determine Helicobacter pylori infection and serum pepsinogen I and II levels.
2. To establish cutoff values for serum markers of precancerous gastric lesions.
3. To classify all cases into gastric cancer risk groups according to the serum marker–based ABCD classification.

This study was conducted using a hospital-based cross-sectional study design. Among individuals aged 32 years and older, upper gastrointestinal endoscopy was performed, stool antigen testing was used to detect H. pylori infection, and serum pepsinogen I, pepsinogen II, and anti-H. pylori antibodies were measured

A total of 94 participants were included in the study, with a male-to-female ratio of 1:1. The cutoff value for pepsinogen I indicating precancerous gastric lesions was PG I ≤ 33 ng/mL, with a sensitivity of 80%, specificity of 64.1%, and a p-value of 0.005. The cutoff value for detecting H. pylori infection was an H. pylori antibody level ≤ 7.85 U/mL, with a sensitivity of 75.4%, specificity of 72%, and a p-value < 0.005. Based on serological markers, 25.5% (n=23) of cases were classified as group A, 38.6% (n=36) as group B, 34% (n=32) as group C, and 3.2% (n=3) as group D.

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According to the ABCD classification, 25.5% of the individuals in the study (Group A) require repeat endoscopy and gastric cancer screening after 5 years, 38.6% (Group B) after 3 years, and 37.2% (Groups C and D) after 1 year.Establishing the serological marker–based ABCD classification helps prioritize gastric cancer risk groups in endoscopic screening practice. By reducing unnecessary repeated endoscopies and ensuring that high-risk individuals undergo closer endoscopic surveillance, this approach contributes significantly to improving the early detection of gastric cancer.