2023 Volume 72 Issue 1 Pages 123-127
The latex immunoassay using the Helicobacter pylori antibody test reagent “H. pylori-latex Seiken” (Denka Co., Ltd.) has been considered to be sufficiently accurate with a cut-off value of 10 U/mL. However, there have been reports indicating the presence of H. pylori infection among antibody-negative patients. We aimed to re-evaluate H. pylori infection among antibody-negative patients with high (3.0–9.9 U/mL) and low (< 3.0 U/mL) negative antibody levels with results of endoscopies conducted alongside antibody tests. From our hospital, we enrolled 53 patients who were endoscopically diagnosed as having chronic atrophic gastritis from 214 patients negative for H. pylori antibodies and no clinical records of H. pylori eradication treatment or histories of gastric cancer. Of these 53 patients, 31 (58%) had low negative antibody levels and 22 (42%) had high negative antibody levels. Re-evaluation of endoscopic findings revealed that 23 (43.4%) of these 53 patients were possibly currently infected with H. pylori or needed further examination to verify infection. Of these 23 patients, 8 had low negative antibody levels (8/31, 25.8%) and 15 had high negative antibody levels (15/22, 68.2%). We discovered false-negative results of the H. pylori antibody test, with a higher ratio in the patients with high negative antibody levels than in those with low negative antibody levels. If these patients were not examined by endoscopy in addition to antibody tests, the infection might have been missed. From our results, it appears necessary to use additional H. pylori tests such as urea breath tests and/or endoscopy for patients with high negative antibody levels.
