Detection of Helicobacter pylori infection via measuring nasal exhaled ammonia with online purge sampling photoionization ion mobility spectrometry

Helicobacter pylori ( H. pylori ) infection is the primary pathogenic factor of chronic gastritis, peptic ulcer, lymphoid tissue lymphoma associated with gastric mucosa and gastric cancer. As H. pylori decomposes urea and produces ammonia, the detection of ammonia in exhaled breath could be used to screen H. pylori infection with unlabeled ordinary urea. Based on the good correlation between alveolar and nasal exhaled ammonia concentrations, online purge sampling coupled with photoionization ion mobility spectrometry (OPS-PIMS) was established for highly sensitive and specific analysis of nasal exhaled ammonia to meet the needs of clinical detection. Using 14 C-urea breath test (UBT) as the reference standard for identifying H. pylori infection, the nasal exhaled ammonia concentration change rate (CCR) achieved an area under the curve (AUC) of 0.92, with an optimal critical value of 20.2 %. The OPS-PIMS method demonstrated a sensitivity of 84.2 %, and a specificity of 92.2 %. The positive predictive value (PPV) was 83.3 % (85/102 cases), the negative predictive value (NPV) was 92.6 % (200/216 cases), and the overall prediction accuracy of 89.6 % (285/318 cases). Receiver operating characteristic (ROC) results showed that the nasal exhaled ammonia measurement is of important clinical significance for the diagnosis of H. pylori infection, allowing infected people to be identified by taking ordinary urea. This approach greatly reduces drug costs, eliminates radioactive interference, and provides better medical treatment. • Online purge photoionization ion mobility spectrometry for sensitive detection of nasal NH 3 . • Concentration change rate of nasal NH 3 after urea intake for the detection of H. pylori infection. • High sensitivity and specificity of receiver operating characteristic for H. pylori diagnosis.