Countercurrent immunoelectrophoresis test for detection of hydatid antigen in the fluid from hydatid cysts: a preliminary report.

The exact aetiology of a suspected hydatid cyst may sometimes be a diagnostic dilemma. One of the recent methods to confirm that the cysts are echinococcal in origin is the demonstration of hydatid antigens in the aspirated cystic fluid. In the present study, we evaluated the use of countercurrent immunoelectrophoresis (CIEP) to detect hydatid antigen in cyst fluids. Antibody used for detecting the antigen consisted of hyper immune sera raised in rabbits after inoculation of crude human hydatid cystic fluid antigen. Fluids were collected post-operatively from a total of 14 hydatid cysts confirmed by surgery and by histopathology. The results of the study show that the test is moderately sensitive detecting antigen in 11 (78.5%) of 14 cyst fluids. The test did not detect antigen in three other cyst fluids. The main advantage is its specificity as it was 100% specific with no reactions in control samples. Even though, sensitivity is not very high, the test is sample, inexpensive, and can rapidly diagnose hydatid aetiology of cysts and may be of help in the diagnosis of hydatid cysts in peripheral parasitology laboratories.