Detection of hydatid antigen in human cyst fluid by reverse latex agglutination test

Diagnosis of cystic echinococcosis (CE) has, sometimes, proved to be of some difficulties whether by serological, radiological, or even by direct microscopic examination of cyst fluid. Therefore, with an aim to apply and assess another method of diagnosis, of pre - intra - or post-operative application, the present work had studied the use of reverse latex agglutination (RLA) test in the diagnosis of CE, as a test that could directly detect hydatid antigen in human cyst fluid samples. The results were reliable when compared with the direct microscopic examination of cyst fluid samples. Also, it was more reliable than indirect haemagglutination test. It showed 100% sensitivity. No false positive reaction was observed with samples from cystic tumours, with a resultant specificity of 100%. Moreover, the test is easy to perform with a visually interpreted results within 2-3 minutes. The reagents are inexpensive, stable and easily available. These merits make the RLA test suitable for the diagnosis of CE, particularly in suspected cases with seronegative results or cases with sterile cysts.