Abstract
BACKGROUND/AIMS: It is difficult to confirm the accurate cutoff value to diagnose Helicobacter pylori (Hp) infection using commercial serology kits. It is reported that there were many cases with present/past infection that even the serum Hp-IgG antibody (HpAb) titers were below the cutoff value (e.g., 10 U/mL for E-Plate®), suggesting that we might overlook many gastric cancer (GC). We investigated an association between gastric cancer risk and serum Helicobacter pylori antibody titers. METHODS: We conducted a primary screening between 2014 and 2015. We performed gastroendoscopy if HpAb titers were ≥3.0 U/mL (i.e., more than measurable limit, E-Plate). These patients were divided into two groups: HpAb = 3.0-9.9 U/mL ("negative-high" group) and HpAb ≥ 10 U/mL; cutoff value ("over-10 U/mL" group). Hp infection status was investigated, and the number of GC patients was counted. RESULTS: Among the 3321 subjects in the primary screening, 56.9% (1891/3321) showed HpAb titers ≥3.0 U/mL; 1314 patients underwent gastroendoscopy. Ten were GC. 421 patients were "negative-high" group; two were GC. After evaluating 381 patients for Hp infection, 22.6%/60.6% was with present/past infection among the "negative-high" group. CONCLUSION: We also found a correlation between HpAb titers and Hp infection status. "Negative-high" group has a risk of GC.