Helicobacter pylori-seropositive rates are decreasing in South Korea. Seroprevalence was 74.3% in 1990, but it decreased to 43.9% in 2016. In Koreans, most gastric cancers are related to H. pylori infection. H. pylori-negative gastric cancers were found only in 2.3% among the 1,833 Korean gastric cancer patients. Despite these facts, the national guideline still recommends biennial gastroscopy for all Koreans aged between 40 and 75 years. Therefore, 8,462,570 (63.1%) Koreans underwent gastric cancer screening among the target population of 13,404,927 individuals in 2021.~In H. pylori-seroprevalent populations, diagnostic criteria for naive status should be strict based on histology, endoscopy, and serum pepsinogen (PG) assay findings. Naive condition should be diagnosed only when both invasive and non-invasive H. pylori tests show negative findings. Furthermore, there should be no intestinal metaplasia and atrophy on serum PG assay, endoscopy, and histology findings in H. pylori-naive participants. Based on those findings, H. pylori infection will be confirmed when invasive tests or urea breath test was positive. H. pylori-naive status will be diagnosed if there was no eradication history, no serologically detected atrophy (PG I ≤70 ng/mL and PG I/II ≤3), and no intestinal metaplasia or atrophy on endoscopy and histology.~This study aimed to determine the validity of blood tests for gastric cancer screening according to the H. pylori infection status. Furthermore, the efficacy of blood tests in discriminating type A (reverse atrophy), type B (atrophy), and non-atrophic gastritis will be analyzed.
Helicobacter pylori infection rate is decreasing in younger population; however, biennial gastroscopy is still recommended for all Koreans aged between 40 and 75 years. This study aimed to validate blood tests for gastric cancer screening according to the infection status of H. pylori (naive, current, and past infection).