Evaluation of the crossed-over electrophoresis test for the immunodiagnosis of human hydatid disease.

The crossed-over electrophoresis (COE) test for hydatidosis was evaluated with sera from preoperative, surgically-confirmed hydatidosis cases, postoperative hydatidosis patients, healthy donors and persons with other parasitic and non-parasitic diseases. The sensitivity and specificity of the test varied with the use of concentrated or unconcentrated serum and when test positivity was based on readings carried out before or after citrate treatment of slides or after their staining. Although the sensitivity of the COE test was higher than that obtained by the immunoelectrophoresis (IEP) test, it was not possible to differentiate hydatid from non-hydatid sera by the former technique. The IEP test based on the detection of the Echinococcus granulosus arc 5 as criterion of positivity was found to be the test of choice for this purpose. No false positive results were obtained in non-hydatid sera.