Evaluation of the indirect haemagglutination test in the diagnosis of amoebiasis.

The IHA test was evaluated in the diagnosis of amoebiasis. Axenically-grown E. histolytica was used as an antigen. A total of 427 sera from symptomatic (intestinal and extra-intestinal) amoebiasis patients. asymptomatic carriers, patients with parasitic intestinal infections other than E. histolytica, and healthy controls were tested. From 288 symptomatic cases of amoebiasis, 232 (80.6 per cent) gave positive reactions. In 93 asymptomatic cases of amoebiasis, 55 (59.1 percent) were seropositive. In testing of sera from 16 subjects with parasitic intestinal infections other than E. histolytica, a low-level positive IHA titres occurred in 2 (12.5 per cent). The test was also positive with a low titre in 3 (10.0 per cent) of the 30 subjects of the healthy control group. The results indicate that the IHA test is of value in the confirmation of intestinal and extra-intestinal amoebic infections especially in cases where the parasite is difficult to demonstrate.