Abstract:

Objective To evaluate the diagnostic value of fasting end-expiratory H₂S, NO, H₂, and CH₄ for colorectal polyps, and to explore the impact of factors such as gender and age on these markers. Methods A total of 245 colonoscopy subjects from the First Affiliated Hospital of China Medical University from January 2024 to December 2024 were included, divided into colorectal polyp group (CP, n=117) and normal control group (NC, n=128). The subject underwent breath test, which used a breath analyzer in a fasting state to test the concentrations of H₂S, NO, H₂, and CH₄.The differences between groups, as well as the results of subgroup analysis of influencing factors, were analyzed to evaluate the diagnostic efficacy of the four gases for colorectal polyps. Results Analyzing the concentrations of H₂S, NO, H₂, and CH₄ gases at fasting end-expiratory of the subjects, it was found that the H₂S level in the CP group was significantly higher than that in the NC group (107.50 ppb vs. 9.00 ppb) (P<0.000 1), while there were no differences of other gases (NO, H₂, CH₄) between the two groups (P>0.05); using colonoscopy and pathological examination as the standard, the AUC for diagnosing colorectal polyps with H₂S concentration was 0.966; males and smokers had higher H₂S concentration (P<0.01). End-expiratory H₂S has high diagnostic efficacy as a novel non-invasive diagnostic marker for colorectal polyps, providing a new strategy for non-invasive screening of colorectal polyps. Conclusions Fasting end-expiratory H₂S concentration is a novel non-invasive diagnostic marker for colorectal polyps, with high diagnostic efficacy, providing a new strategy for the non-invasive screening of colorectal polyps.

Key words: Colorectal polyp (CP), Non-invasive diagnosis, Expiratory biomarker, Hydrogen sulfide (H₂S), Colonoscopy