The present disclosure relates to an article for detecting a disinfectant via visual feedback. The article have a first substrate with a first major surface and opposite ends. The article also comprises a process indicator disposed on at least a portion of the first major surface. The process indicator reacts with at least one liquid disinfectant selected from the group consisting of glutaraldehyde, ortho-phthalaldehyde, hydrogen peroxide, peroxyacetic acid, and combinations thereof. The process indicator can be formed from a synthetic amine-containing polymer derived from polyethylenimine (PEI). The article can have a flow channel that is formed by a portion of the process indicator and that extends between the opposite ends. The disclosure also relates to a kit containing the article as well as a method of using the article in a disinfection process. The article is used to diagnose issues in an automated endoscope reprocessors (AERs).