2190 Table 1 Comparison of different immunodiagnostic tests with EITB as the gold standard method for detection of antibodies against T. solium cysticerci in serum samples from epileptic patients Negative Total EITB Positive Immunodot blot Tsol-p27 Positive 13 Negative 2 Total 15 Commercial ELISA Positive 13 Negative 2 Total 15 Western blot Tsol-p27 Positive 13 Negative 1 Total 14 Western blot TsolHSP36 Positive 13 Negative 8 Total 21 5 87 92 5 87 92 4 87 91 14 87 101 18 89 102 18 89 102 17 88 105 27 95 122 Dorny 2010; Garcia et al. 2005; Mandal et al. 2008; Simac et al. 1995). The most specific test developed thus far is EITB, with reported specificity of 100% and sensitivity of 98%. However, the sensitivity of this test drops considerably in cases involving single cysts in the brain (Singh et al. 1999). The EITB method uses an enriched fraction of gly- coproteins prepared by lectin-affinity purification from an extract of intact cysticerci (Deckers and Dorny 2010; Tsang et al. 1989). Some of the drawbacks of EITB are that it requires sophisticated equipment and trained personnel to perform the test, it is not suitable for field studies, and it is seldom affordable in countries where cysticercosis is en- demic (Deckers and Dorny 2010; Dorny et al. 2003). There- fore, research projects have been focused on developing new serological diagnostic tools that offer sensitivity and specificity, and are easy to perform in poorly equipped laboratories. The aim of the present study was to study the efficacy of an immunodot blot using the Tsol-p27 protein (immunodot blot Tsol-p27) in comparison with various immunodiganostic formats and antigens. More specifically, a commercial ELISA and the antigens TsolHSP36 and Tsol- Table 2 Sensitivity, specificity, and PPV and NPV values of the immunodiagnostic tests used to diagnose T. solium cysticerci in serum samples from epileptic patients Immunodiagnostic test Immunodot blot Tsol-p27 Commercial ELISA Western blot Tsol-p27 Western blot TsolHSP36 Parasitol Res (2012) 110:2187–2191 p27 in Western blot formats (Western blot Tsol-p27/ TsolHSP36) were included in the serological evaluation. The Tsol-p27 antigen was efficiently expressed in E. coli as a fusion protein with his and GST fusion parts, and it was purified in two steps using glutathione-agarose and his- selected nickel beads. Our immunodot blot technique used a highly purified Tsol-p27 antigen, which decreased the background (e.g., E. coli antigen) seen in Western blot analysis using one-step purified Tsol-p27 antigen (Fig. 1, lane 3). The EITB results were considered confirmatory of human cysticercosis and were used as a standard to assess the performance of the different diagnostic methods. A total of 100 human serum samples from epileptic patients were examined by EITB, and antibodies to T. solium cysticercus were detected in 13 of those samples. In our study, immunodot blot Tsol-p27 was comparable to Western blot Tsol-p27 with regard to specificity (97.8% vs. 95.6%) but not sensitivity (86.7% vs. 76.4%), and it was similar to ELISA regarding both specificity (97.8% vs. 94.6%) and sensitivity (86.7% vs. 86.7%). Western blot- TsolHSP36 showed lower specificity (86.1%) and sensitivity (61.9%) compared to the other immunodiagnostic methods. It has previously been noted that the Tsol-p27 antigen has po- tential for diagnosis of human cysticercosis. In an earlier study (Salazar-Anton and Lindh 2011), Western blot showed that antibodies in serum from NCC patients, but not those in serum from a control group, could identify the Tsol-p27 antigen. Furthermore, it has been reported that using ELISA to detect specific antibodies against T. solium cysticerci in samples from patients with suspected cysticercosis provides a useful tool for diagnosing this disease in humans (Rosas et al. 1986; Simac et al. 1995). However, the results of ELISA used for this purpose vary significantly (Bucardo et al. 2005; Carpio 1998), and the discrepancies between studies can be explained by the use of disparate criteria for patient selection and differ- ent methods as the gold standard. In our investigation, West- ern blot TsolHSP36 offered lower sensitivity and specificity compared to immunodot blot Tsolp-27, Western blot Tsol- p27, and the commercial ELISA. Notably, the TsolHSP36 antigen has previously been described as an antigenic target in the diagnosis of human cysticercosis (Ferrer et al. 2005). We also used immunodot blot Tsol p-27 to analyze serum samples from patients with positive or negative serology for Chagas disease, and none of those sera recognized the Tsol- p27 antigen. There is an overlap in the epidemiology of Sensitivity Specificity 86.7% 86.7% 76.4% 61.9% 97.8% 94.6% 95.6% 86.1% PPV 86.7% 72.2% 76.5% 48.1% NPV 97.8% 97.8% 98.9% 91.5%