Comparison of the FLOTAC-400 dual technique and the Formalin-Ether Concentration Technique for the diagnosis of human intestinal protozoa infection

There is a need for accurate diagnosis of intestinal parasite infections in humans, but currently available copromicroscopic techniques have shortcomings, such as low sensitivity. We compared the diagnostic accuracy of a further modified version of the recently developed FLOTAC technique with the widely used formalin-ether concentration technique (FECT) for the detection of intestinal protozoa in human stool samples. Formaldehyde-preserved stool samples from 108 individuals in Cote d'Ivoire were subjected to the FLOTAC-400 dual technique using two different flotation solutions (FS), and the FECT. Stool samples were examined according to computer-generate random lists by an experienced laboratory technician blinded for the results of each method. Both methods detected the same eight intestinal protozoa species. Whilst the FLOTAC-400 dual technique (results from both FS combined) found higher prevalences of Entamoeba coli (77.8% vs. 71.3%, p>0.001), Blastocystis hominis (20.4% vs. 13.0%, p=0.458) and Giardia intestinalis (8.3% vs. 6.5%, p>0.001), the FECT detected higher prevalences of Entamoeba histolytica/E. degrees dispar (27.8% vs. 20.4%, p=0.019) and four species of non-pathogenic intestinal protozoa. The diagnostic agreement between the two methods differed considerably depending on the intestinal protozoa investigated (kappa measures; range, 0.01-0.46). Our study confirmed that the FLOTAC-400 dual technique can be utilized for diagnosis of intestinal protozoa infections in humans. Since FLOTAC is a sensitive technique for the detection of soil-transmitted helminths and Schistosoma mansoni, it might become a viable copromicroscopic technique for the concurrent diagnosis of helminths and intestinal protozoa infections