A single-step immunochromatographic test for the detection of Entamoeba histolytica antigen in stool samples

A rapid, single step, sensitive and specific immunochromatographic test for the detection of E. histolytica antigens in the stool samples is described. Monoclonal antibody AC55 specific for E. histolytica was used as capture antibody on nitrocellulose sheet. The same antibody was conjugated to colloidal gold to detect the presence of antigen. In this test, multiple steps of washing, incubation, etc. are not required and there is no need for secondary colour development as gold particles produce a typical reddish, purple colour, when they bind to the solid phase at the site of immune reaction. 151 stool samples from patients with suspected amoebiasis were screened by this assay. Sensitivity of the test was found to be 97.6% and specificity 92.6%. 25 polyxenic E. histolytica cultures and other cultures were also tested. The test did not show positive reaction with other intestinal parasites.