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.

What is this article about? Coloring parasites during fecal exams has been widely used to find parasites in human feces. We searched for articles that could help us to answer the question 'How do dyes give color to parasites?'. Then, we filtered the information from a total of 1334 articles to 35.What were the results? Cryptosporidium spp. and Microsporidia are microbes that can be seen only through a microscope. Researchers were interested in these two species in the last 40 years. Differentiating parasites from dirt on a glass slide is the main problem researchers are trying to solve. The way the light goes through parasites under a microscope, variation of staining, size and temperature of dyes have been explored to identify what gives better results in coloring protocols.What do the results of the study mean? Little is known about the chemical interaction between dyes and parasites. On the other hand, there are many studies on how good coloring methods are and comparing protocols. An alternative to the conventional approaches in staining parasites is the use of computational tools to reduce doubt in the exam interpretation by technicians.