Comparison of indirect fluorescent-antibody amoebic serology with counterimmunoelectrophoresis and indirect hemagglutination amoebic serologies.

Patients ranged from those with no prior diagnosis of or suspected exposure to Entamoeba histolytica to those with proven amoebic liver abscesses (extraintestinal disease). A comparison of serologies from patients with proven and suspected amoebiasis or possible past exposure revealed good correlation between the indirect fluorescent antibody (IFA) procedure and the other methods used, counterimmunoelectrophoresis and indirect hemagglutination. Titers from patients with proven extraintestinal amoebiasis were in the expected high range previously reported by other authors. Patients with clinical histories suggestive of exposure to E. histolytica but no proven disease had lower titers which indicated possible background exposure. The IFA procedure provides a rapid method of antibody detection; results obtained on an emergency basis provide essential information in making the diagnosis of amoebic abscess, pyogenic abscess, or tumor. The IFA procedure is rapid, reliable reproducible, and relatively inexpensive to perform, provided a good source of antigen is consistently available.