Staining blindly: an update on coloring techniques for fecal smears in parasitology: a scoping review

Abstract

Dye application for parasite highlighting in the Ova and Parasite exam is a common practice in parasitology diagnosis. Methods: A scoping review investigated how staining solutions interact with parasite structures. After screening 1334 papers, 35 met eligibility criteria. Results: Differentiating background from foreground in the fecal smear under light microscopy is the core of the research on this topic. Refractivity, unevenness of staining, size and temperature were explored to enhance staining protocols. Cryptosporidium spp. and Microsporidia were the main studied species. Conclusion: Studies on diagnostic efficacy outperform those that elucidate the physical–chemical interaction between dyes and parasites. An alternative approach involves technicians using computational tools to reduce subjectivity in fecal smear interpretation, deviating from conventional methods.