Helicobacter pylori and ammonia concentrations of whole, parotid and submandibular/sublingual saliva

The aim of this study was to determine the ammonia concentration in whole, parotid and submandibular/sublingual saliva of healthy volunteers using the indophenol direct method. It also investigated the hypothesis that higher saliva ammonia concentrations are associated with the presence of Helicobacter pylori (H. pylori) in the oral cavity. In healthy volunteers, the mean ammonia concentration of whole saliva (2574 µmol/l) was significantly higher ( P <0.0001) than the mean ammonia concentration of both parotid (238 µmol/l) and submandibular/sublingual (355 µmol/l) saliva. In whole saliva, no difference in ammonia concentration was found between healthy controls and dyspeptic patients (mean ammonia values 2574 and 2489 µmol/l respectively, P =0.7). In addition, no significant differences were observed in the salivary ammonia concentration between dyspeptic patients with and without H. pylori carriage. It is concluded that the ammonia concentration in parotid and submandibular/sublingual saliva does not differ, but is significantly lower than the ammonia concentration of whole saliva. This difference is not due to carriage of H. pylori with its strong urease activity. Therefore, the determination of ammonia in whole saliva is an inappropriate screening test for patients being at risk for (chronic) gastritis and peptic ulcer disease.