Coproantigen versus microscopic examination for diagnosis of Gardia Lamblia and Entameba Histolytica infection in children in Banha Teaching Hospital

Abstract

Background: Giardia lamblia (G. lamblia) and Entamoeba histolytica (E. histolytica) are of the most common protozoan enteric pathogen in humans. Their laboratory diagnosis mainly consists of direct microscopic examination of stool specimen for trophozoites and/or cysts. However, due to intermittent fecal excretion of the parasite, the patient may be misdiagnosed and infecting others. Recently, immunological testing of stool (coproantigen) for E histolytica G lamblia has been reported as a more sensitive mean for their diagnosis. Aim of Work: Evaluation of the efficacy of coproantigen detection by ELISA technique in comparison to direct microscopical examination for diagnosis of Entamoeba histolytica and/or Giardia lamblia. Patients and Methods: One hundred ten children were included in this simple comparative study. They were divided into three groups: - Group (1) included 40 children with dysentery their stools were examined for E. histolytica, - Group (2) included 40 children with abdominal complaints their stools were examined for G. lamblia, - Group (3) included 30 normal children their stools were examined for detection of both E histolytica and G. lamblia Results: Group (1) by microscopic examination 35% were positive for trophozoites and/or cysts and 65% were negative while by Coproantigen test 47.5% were positive and 52.5%were negative[sensitivity 73%, specificity 100% and NPV 80.7%]. Group (2) by microscopic examination 27.5%were positive for trophozoites and/or cysts and 72.5% were negative while by Coproantigen test 37.5% were positive and 62.5% were negative [sensitivity 73.3%, specificity 100%,PPV 100% and NPV 86.2%] Group (3) For E. histolytica :by microscopic examination 30% were positive for trophozoites and/or cysts and 70% were negative while by Coproantigen test 23.3% were positive and 76.7% were negative[sensitivity 100%, specificity 91.6% ,PPV 77.7% and NPV 100%] For G. lamblia: by microscopic examination 16.6% were positive for trophozoites and/or cysts and 83.4% were negative (while by Coproantigen test 26.6% were positive and 73.4% were negative [sensitivity 62.5%, specificity 100% , PPV 100% and NPV 89.2%]. Conclusion: Coproantigen ELISA technique is a rapid and effective method with high sensitivity and specificity for diagnosis of E. histolytica and G. lamblia