Diagnosis of amebic liver abscess and intestinal infection with the TechLab Entamoeba histolytica II antigen detection and antibody tests

A noninvasive diagnostic test for amebic liver abscess is needed, because a mebic and bacterial abscesses appear identical on ultrasound or computer to mography and because it is rarely possible to identify Entamoeba histolytic a in stool specimens from patients with amebic liver abscess. Here we repor t a method of detection in serum of circulating E. histolytica Gal/GalNAc l ectin to diagnose amebic liver abscess, which was used in patients from Dha ka, Bangladesh. The TechLab E. histolytica II test (which differentiates th e true pathogen E. histolytica from Entamoeba dispar) detected Gal/GalNAc l ectin in the sera of 22 of 23 (96%) amebic liver abscess patients tested pr ior to treatment with the antiamebic drug metronidazole and 0 of 70 (0%) co ntrols. After 1 week of treatment with metronidazole, 9 of 11 (82%) patient s became serum lectin antigen negative. The sensitivity of the E. histolyti ca II antigen detection test for intestinal infection was also evaluated. A ntigen detection identified E. histolytica infection in 50 samples from 1,1 64 asymptomatic preschool children aged 2 to 5 years, including 16 of 16 (1 00%) culture-positive specimens. PCR analysis of stool specimens was used t o confirm that most antigen-positive but culture-negative specimens were tr ue-positive: PCR identified parasite DNA in 27 of 34 (79%) of the antigen-p ositive, culture-negative stool specimens. Antigen detection was a more sen sitive test for infection than antilectin antibodies, which were detected i n only 76 of 98 (78%) amebic liver abscess patients and in 26 of 50 (52%) p atients with intestinal infection. We conclude that the TechLab E. histolyt ica II kit is a sensitive means to diagnose hepatic and intestinal amebiasi s prior to the institution of metronidazole treatment.