A method for detecting Helicobacter pylori in a subject's gastroenteral tract involves measuring a change in resistance of an electronic or electrochemical sensor, notably a polypyrrole film, on exposure to gas from the subject's lungs and/or stomach. Depending on the magnitude of the change (if any) a positive or negative result is indicated visually by electronics means. Two sensors are used, one of which receives a sample of gas which has passed through an amonia-absorbing means to provide a corrected baseline value for the ammonia. The invention also provides apparatus suitable for carrying out the method.
Ratcliffe, N. M., Teare, C., Dunn, C., Cowell, D., Penault, C., Chambers, P., & Black, M. (2003). Detection of helicobacter pylori. US6509169 B2