Comparison of the Kato-Katz, Wet Mount, and Formol-Ether Concentration Diagnostic Techniques for Intestinal Helminth Infections in Ethiopia

Abstract

Objective. The aim of this study was to evaluate the operational characteristics (sensitivity and negative predictive value (NPV)) of wet mount, formol-ether concentration (FEC), and Kato-Katz techniques for the determination of intestinal parasitic infections. Method. A total of 354 faecal specimens were collected from students in Northwest Ethiopia and screened with Kato-Katz, wet mount, and FEC for the presence of intestinal parasitic infection. Since a gold standard test is not available for detection of intestinal parasites, the combined results from the three methods were used as diagnostic gold standard. Result. The prevalences of intestinal parasites using the single wet mount, FEC, and Kato-Katz thick smear techniques were 38.4%, 57.1%, and 59%, respectively. Taking the combined results of three techniques as a standard test for intestinal parasitic infection, the sensitivity and negative predictive value of Kato-Katz is 81.0% (confidence interval (CI) = 0.793–0.810) and 66.2% (CI = 0.63–0.622), respectively. The FEC detected 56 negative samples that were positive by the gold standard, indicating 78.3% (CI = 0.766–0.783) and 63.2% (CI = 0.603–63) sensitivity and NPV, respectively. Furthermore, Kato-Katz detects 113 cases that were negative by a single wet mount. The κ agreement between the wet mount and Kato-Katz methods for the diagnosis of Ascaris lumbricoides and hookworm was substantial (κ = 0.61 for Ascaris lumbricoides, κ = 0.65 for hookworm).

Evaluation of Hookworm Diagnosis Techniques from Patients in Amhara Region, Ethiopia: Cross sectional study

“…Moreover, the presence of large stool debris materials in the DWMM may conceal the parasitic ova. The sensitivity of DWMM in this study (37%) is similar with other studies done in Ethiopia (25,27). This suggests that DWMM has resulted in around 63% false negative reports during hookworm diagnosis.…”

“…The speci city of all of the stool examination methods described in this study was 100%, and this is in line with ndings of a study done in Gondar which revealed that DWMM, FEC and KK had greater than 97% of sensitivity (27). The current study also analyzed the level of agreement of the various types of hookworm diagnosis methods with composite reference standard.…”

“…Formol ether concentration technique and KK were also ranked as the third (44.3%) and fourth (38.2%) sensitive tests, respectively in this study. However, this is lower than the previous study carried out in Gondar in which their sensitivities were reported from 69-72.4% (27). The observed differences in the sensitivities among different studies could be due to the infection intensity variation.…”

Evaluating the Performance of Diagnostic methods for soil transmitted helminths against the “Gold” standard in the Amhara National Regional State, Northwest Ethiopia

“…However, the result of the present study is in contrary to previous studies done in Peusangan Bireuen [33] and Ethiopia [34,35]. These differences in diagnostic performance might be due to stool sample size, number of slides prepared for diagnosis, inter personal skill variations and technical errors of the two methods.…”

Comparison of two diagnostic techniques to determine the prevalence of <i>Schistosoma mansoni</i> infections in Cameroonian school children

“…Contradictory results have been reported in the literature on the effectiveness of Kato-Katz and Formolether techniques in the detection of gastrointestinal parasites in faeces. Some authors have noted that the Kato-Katz technique was better and significantly more sensitive than the other method (18)(19) while others have reported that the Formol-ether technique had a better sensitivity than the Kato-Katz method (20)(21). According to Knight et al, (22), the concentration of eggs in the faeces enabled the detection of more patients infected with S. mansoni when the Formol-ether technique was used.…”