Diagnostic Efficacy of IgG ELISA in Hydatid Disease : A Retrospective Study

Most serodiagnostic techniques have been evaluated for diagnosis of cystic hydatid disease caused by Echinococcus granulosus. Each, to varying degrees, has been shown to give false results, with considerable variation between laboratories. The comparative retrospective study was done concerning the sensitivity of the different commercially available IgG ELISA kits based on previous laboratory records of 55 patients diagnosed as hydatid disease either intraoperatively or post operative histopathology with different cyst locations. In house ELISA, DRG IgG kit, Nova Lisa kit and Ridascreen IgG kit were studied. Specific IgG ELISA AgB (antigen B-rich fraction) was the most sensitive test (100%) and the least sensitive tests were the In House ELISA (75%), DRG (75%), Nova Lisa (66.66%), these results coincide basically with the findings of most researchers. ABBREVIATIONS CE: Cystic Echinococcosis, ELISA: Enzyme-linked immunosorbent assay, IgG: Immunoglobulin G INTRODUCTION Cystic echinococcosis (CE), known as hydatid cyst or hydatid disease, is a parasitic zoonosis caused by the larval stage of Echinococcus granulosus (E. granulosus) which accounts for 95% of human echinococcosis. Dogs and other canids harbor the adults tape worm and herbivores act as intermediate host and become infected through ingestion of parasite’s eggs. Human acquire the infection by accidental ingestion of E. granulosus eggs [1]. CE with its significant economic and medical impact constitutes an important public health problem in many developing countries [2,3]. Worldwide, echinococcosis causes an estimated annual loss of US $194,000,000. An estimated 1.2 million people worldwide are affected by CE and the disease accounts for annual estimate of 3.6 million DALYs (dis ability adjusted life years) through the world [4]. Early and proper diagnosis of CE can provide appropriate management and suitable treatment of the disease [5]. Diagnosis of CE is mainly confirmed through a combination of relevant history, serological testing, along with imaging approaches. A variety of serological methods have been developed and used for immunodiagnosis of CE in recent years, including indirect hemagglutination, immunoblotting, enzymelinked immunosorbent assay, indirect fluorescent-antibody, latex agglutination test, and immunochromatography test [6,7]. For the development of these assays different antigens from adult worm, protoscolices, worm eggs or hydatid cyst fluid have been defined, purified and evaluated in the aforementioned serological tests [8]. Diagnosis of CE has drastically improved during the last two decades. Progress in methods for antigen purification, cloning expression and purification of E. granulosus recombinant antigens, and defining and synthesis of immunodominant peptides contributed to this development [9]. Nevertheless, immunodiagnosis of CE is still problematic. Commercially available sero logical tests show unsatisfactory performance. The lack of standardization of immunodiagnostic assays and also antigen preparation contribute to discrepancy in results reported in different laboratories. Cyst size, stage and location as well as patients characteristics may be accounted for the discrepancy of the same test performance in different clinical diagnostic laboratories [10-12]. Hence, serological assays still have a complementary role to imaging in the diagnosis of CE. Low sensitivity (up to 30% of false negativity) and also low specificity (up to 25% of false positivity) make serological results difficult to interpret. [13-15]. With this context, this study was conducted to evaluate and compare the diagnostic efficacy of four ELISA systems in our department. MATERIALS AND METHODS This retrospective study was done in Department of Microbiology; Sher-i-Kashmir Institute of Medical Sciences, North India on patients who underwent surgery for suspected hydatid cysts of liver, lung, bladder, 4th ventricle of brain from Kakru et al. (2017) Email: Ann Clin Pathol 5(1): 1104 (2017) 2/4 Central Bringing Excellence in Open Access 