TF-Test Modified as New Diagnostic Tool for Human Enteroparasitosis

Intestinal parasitosis is highly prevalent worldwide, being among the main causes of illness and death in humans and currently, laboratory diagnosis of the intestinal parasites is accomplished through manual technical procedures, mostly developed decades ago, which justifies the development of more sensitive and practical techniques.

The three fecal tests (TF-Test) conventional parasitological technique has been providing effective and practical enteroparasitosis diagnosis for clinical analysis laboratories, especially by collecting three separate stool samples on alternate days and processing them at once with the laboratory procedure of parasite concentration and elimination of fecal debris by the principle of centrifugal sedimentation.


Scientists at the University of Campinas (São Paulo, Brazil) collected a total of 457 stool samples which were obtained from two sources in enteroparasitosis endemic areas. One source was from 185 children aged between 9 months and 7 years, who were enrolled in two municipal elementary schools located in the southwestern region of Campinas. The other source was from 272 individuals aged between four and 72 years, who attended public basic health units located in the south and southeastern regions in the municipality of Campinas. Samples were collected in TF-Test collector tubes for subsequent laboratory processing.

The new parasitological technique referred to as TF-Test Modified, was compared to three conventional parasitological techniques: TF-Test Conventional; Rugai, Mattos & Brisola; and Helm Test/Kato-Katz. Among the stool samples of 457 volunteers, 1,828 tests were performed by the four parasitological techniques resulting in detection of 14 species, from which six were related to protozoa and eight related to intestinal helminths. The sum of positive cases of all four techniques was 308 parasitic structures, including cysts, eggs, and larvae. Among them, 303 were identified by TF-Test Modified, 256 by TF-Test Conventional, 23 by Helm Test, and 19 by Rugai, Mattos & Brisola technique.TF-Test Modified allowed the preparation of temporary smears stained with Lugol's iodine solution, with a high concentration of parasite species, and largely free of fecal debris and leading to the diagnosis of Blastocystis hominis and other protozoa, by giving a sharper image.

The authors concluded that the modifications added to this new diagnostic technique provided high diagnostic values, increasing the sensitivity by 15.26% when compared to the second-best technique, TF-Test Conventional. The present study demonstrated that the TF-Test Modified technique can be comprehensively used in qualitative diagnosis of humans’ intestinal helminths and protozoa. The gain in diagnostic sensitivity provided by this new technique should have a laudable contribution to the laboratorial diagnosis, population surveys, and intestinal parasites control. The study was first published online on May 15, 2015, in the Journal of Clinical Laboratory Analysis.

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