Entamoeba histolytica IgG (Amebiasis)

Amebiasis is the disease caused by the protozoan parasite Entamoeba histolytica. This organism is endemic throughout the world in developing countries, and can be found in immigrants and travelers from these areas. The disease usually manifests with intestinal symptoms. In a minority of cases, the organism will become extra-intestinal and lead to abscess formation in different organs. Of the organs that could be affected, the liver is the most common site. Typically, the organism can no longer be found in the feces once the disease goes extra-intestinal. Serological tests are useful in detecting infection by E. histolytica if the organism goes extra-intestinal and in excluding the organism from the diagnosis of other disorders (e.g. chronic liver diseases, ulcerative colitis, etc.). This serology test should not be used for detecting intestinal infections. An Ova & Parasite (O&P) test or an E. histolytica fecal antigen assay is the proper assay for intestinal infections. Since antibodies may persist for years after clinical cure, a positive serological result may not necessarily indicate an active infection. A negative serological result however can be equally important in excluding suspected tissue invasion by E. histolytica.