A comparative study of formalin-ethyl acetate sedimentation technique and Mini Parasep(®) solvent-free method in the rapid diagnosis of intestinal parasites

BACKGROUND: Stool microscopy and concentration techniques are the two most important and necessary aspects of diagnostic parasitology. In an era when there is increased disease burden due to intestinal parasites, an early and appropriate diagnosis is warranted. Direct microscopy is usually labor intensive and tedious. MATERIALS AND METHODS: Thirty-two fresh fecal specimens from patients presenting with eosinophilia and/or anemia (hemoglobin levels <10 g%), HIV-positive patients, and in patients clinically suspected of harboring parasites, were collected for the study. All the positive samples were processed by both the standard methodology, i.e., formalin-ethyl acetate sedimentation technique and Mini Parasep(®) SF method, by the standard operating procedure of our laboratory and the manufacturer's instruction. Stool pellet concentrates were subjected to saline/iodine wet mount, modified acid fast staining for intestinal coccidian parasites and trichrome staining for Blastocystis hominis. The average number of organisms counted in 0.5 ml of pellet was used for comparison of the two techniques. RESULTS: The morphology of eggs was maintained in both the techniques; however, the wet mount prepared from the sedimentation technique had more background fecal debris in comparison to the Parasep(®) technique. The parasite yield was equal for both the techniques while Mini parasep had the advantage of less distortion of parasite morphology. CONCLUSION: We found that Parasep(®) offered a better parasitic yield, a better workflow capacity, and a reduced turnaround time, which would further benefit resource-restrained laboratories and those with a high sample turnover.