An apparatus comprising means configured to:determine, based on a sound generated by reaction of a substance or composition within the digestive system of a human or animal body, one or more of the presence and concentration of an analyte indicative of a digestive disorder, wherein the substance or composition forms at least part of an ingestible body and is configured to react on exposure of the ingestible body to the analyte； andprovide the determination of the presence and/or concentration of the analyte for use in diagnosing the digestive disorder of the human or animal body.
