Disclosed is a method of identifying if a subject is sufficiently prepared to permit successful colonoscopic examination, the method comprising the steps of: (a) obtaining a stool sample from a subject having undergone preparation for a colonoscopic examination; (b) analysing the sample to detect the presence and/or amount of faecal matter, if any, in the stool sample; and (c) from the analysis in step (b), identifying whether the subject has been sufficiently prepared.