Brief Communication: Comparison of formol-acetone concentration method with that of the direct iodine preparation and formol-ether concentration methods for examination of stool parasites

Background: Formol-ether concentration technique is taken as a gold standard method to detect most intestinal parasites; however, because of its low safety and hazardous impact a need for better technique has a paramount importance. Objective: To evaluate a formol- acetone concentration method in comparison with the conventional direct iodine preparation and formol- ether concentration methods in detecting intestinal parasites. Methods: A total of 382 stool samples were collected from Tseda elementary school children, in 2006. Samples were processed and examined using formol-acetone concentration, the direct iodine stained smear, and formol-ether concentration methods. Results: Formol-ether detected 79.1% of parasites followed by formol-acetone (73.6%) and direct iodine preparation (50.3%). Statistical (P< 0.05) difference was observed for the detection of over all positivity of any parasites between the two concentration methods. However, the sensitivity, specificity, and positive predicative value of formol-acetone were 88.1%, 81.3%, and 94.7%, respectively respective to formol-ether method. Almost similar detection ability was also observed by the two concentration methods for A. lumbricoids, H. nana, T. trichuira, and S. stercoralis. However, there was difference in the detection rate of hookworm and S. mansoni. Conclusions: for safety and hazard free laboratory set up, this new method might be used as an alternative choice for formol-ether concentration method. [Ethiop. J. Health Dev. 2010;24(2):148-151]