Comparative sensitivity of six serological tests and diagnostic value of ELISA using purified antigen in hydatidosis

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 study was made concerning the sensitivity of the immunodiagnostic methods based on 58 sera from hydatid disease with di fferent cyst locations. Latex agglutination, immunoelectrophoresis (IEP), a nd specific IgE, IgG enzyme-linked immunosorbent assay (ELISA) tests were s tudied. Specific IgG ELISA AgB (antigen B-rich fraction) was the most sensi tive test (96.5%) and the least sensitive tests were specific IgE ELISA (24 .1%) and IEP (25.8%). The low sensitivity of these two tests was due partly to the low reactivity detected in the sera of patients with lung hydatidos is. Initial laboratory studies showed purified antigens to be preferable to crude cyst fluid, regardless of the type of test used. For this reason, we evaluated the sensitivity and specificity of ELISA by using the purified a ntigen-B-rich fraction. In all, 117 sera were examined: 78 sera from patien ts with hydatidosis surgically confirmed, 15 sera from healthy control subj ects, and 24 sera from patients with diseases other than hydatidosis. The m ethod gave good results: 93.5% sensitivity, 89.7% specificity, and 92.3% di agnostic efficacy. J. Clin. Lab. Anal. 15:14-18, 2001. (C) 2001 Wiley-Liss, Inc.