This is a multi-center, non-randomized, open label study. Subjects will be enrolled if they are deemed eligible given the inclusion criteria. Subjects who meet all inclusion criteria and none of the exclusion criteria will be entered into the study. Subjects will be exposed to non-radioactive 13C-Urea with citric acid, and may submit a stool sample or undergo endoscopy for Rapid Urease Test and Histology samples. Center(s) will house a PyloPlus UBT Analyzer to document results. PyloPlus Analyzer results shall remain blinded to the investigator and treating physician. No patient management decisions should be made based on the investigational PyloPlus UBT System. Treating physician will either prescribe a H. pylori Stool Antigen Test through P4 Diagnostics, along with another Urea Breath Test using Breath ID, or patient will undergo Endoscopy to provide a composite reference method consisting of Rapid Urease Test and Histology. These will act as the comparators to the PyloPlus Urea Breath Test System.