A collection of reagents and other associated materials intended to be used for the qualitative and/or quantitative detection of nucleic acid from multiple types of microorganisms associated with gastrointestinal disease, in a clinical specimen, using a microarray method. Microorganisms detected may include bacteria, viruses, fungi and/or parasites such as, but are not limited to Salmonella, Shigella, Campylobacter, Escherichia coli (E. coli), Norovirus, Rotavirus, Clostridium difficile, Giardia, Bacillus and/or Vibrio species.