Detection of intestinal protozoa in the clinical laboratory

Despite recent advances in diagnostic technology, microscopic examination of stool specimens remains central to the diagnosis of most pathogenic intestinal protozoa. Microscopy is, however, labor-intensive and requires a skilled technologist. New, highly sensitive diagnostic methods have been developed for protozoa endemic to developed countries, including Giardia lamblia (syn. G. intestinalis/G. duodenalis) and Cryptosporidium spp., using technologies that, if expanded, could effectively complement or even replace microscopic approaches. To date, the scope of such novel technologies is limited andmay not include common pro-tozoa such as Dientamoeba fragilis, Entamoeba histolytica, or Cyclospora cayetanensis. This minireview describes canonical ap-proaches for the detection of pathogenic intestinal protozoa, while highlighting recent developments and FDA-approved tools for clinical diagnosis of common intestinal protozoa. Protozoan infections significantly contribute to the burden ofgastrointestinal illness worldwide. While the prevalence of these infections is low in the United States, sporadic outbreaks, including the 2013 outbreak of cyclosporiasis in the United States, underscore the continued burden of disease these organisms pres-ent in developed countries. Giardia, Cryptosporidium spp., Dien-tamoeba fragilis, Entamoeba spp. (including nonpathogenic spe-cies), Blastocystis spp., and Cyclospora cayetanensis are the mos