THE FORMOL-ETHER CONCENTRATION TECHNIQUE FOR INTESTINAL PARASITES: COMPARING 0.1 N SODIUM HYDROXIDE WITH NORMAL SALINE PREPARATIONS

Abstract. The formol-ether method is a widely used technique for stool examination. We performed a comparative study of 0.1 N sodium hydroxide (NaOH) and normal saline preparation for the formol-ether technique in the detection of intestinal parasites. Of 30 parasite-containing stool samples, 22 (73%) were positive by 0.1 N NaOH and 18 (60%) were positive by normal saline. The detection rate of both preparations was not significantly different (p>0.05). MATERIALS AND METHODS Stool specimens were collected from people who were living in an endemic area of Maung Rung village, Huai Thalaeng district, Nakhon Ratchasima Province on the assumption that they were harboring Opisthorchis viverrini eggs. All specimens were examined by simple smear with iodine and concentration technique using standard normal saline comparing to 0.1 N sodium hydroxide preparations. Two preparations were used for the formol-ether technique: one with 0.1 N sodium hydroxide (NaOH) and the other with normal saline. A total of 30 parasitecontaining stool specimens were studied. The formolether technique used in this study was that described b