Diagnosis of Intestinal Parasitoses: Comparison of Two Commercial Methods for Faecal Concentration Using a Polyparasitized Artificial Liquid Stool

Abstract

As conventional faecal concentration methods for parasite detection may carry health risks due to the toxicity of the solvents used (ether, acetyl-acetate), we compared parasite recovery obtained with the new solvent-free EasyPara® kit (Servisol, Meudon, France), which consists of a single-use tube containing a porosity gradient filter ( 200 to 400 µm), and that obtained with the Para-Selles® system (Fumouze Diagnostics/Sofibel, Levallois-Perret, France), an ethyl-acetate solvent sedimentation method routinely used in our laboratory.Both kits were used as recommended by their manufacturers. Both kits concentrate parasites in a pellet, which is suspended for microscopic examination. Parasites were identified on the basis of their morphology. The numbers of parasites recovered in the total pellets were compared between the kits. To compare the detection thresholds of the kits, we tested a liquid polyparasitized stool sample prepared by pooling clinical parasitized stool samples (protozoa and helminths) from parasitized patients consulting our hospital and stored in our collection and diluting it with saline solution. Using the liquid polyparasitized stool sample, the recovery concentrations for Entamoeba histolytica/dispar, Entamoeba coli and Angystrongyloides stercoralis larvae were significantly different with the two kits but no difference was observed for Giardi intestinalis cysts and Ascaris, tapeworm egg detection.Parasite recovery was better with the EasyPara® kit than with Para-Selles®, probably owing to the presence of an original porosity gradient filter.