The noninvasive diagnosis of
amebic liver abscess is challenging, as most patients at the time of diagnosis do not have a concurrent intestinal
infection with Entamoeba histolytica. Fecal testing for E. histolytica parasite
antigen or
DNA is negative in most patients. A real-time PCR assay was evaluated for detection of E. histolytica
DNA in blood, urine, and saliva samples from
amebic liver abscess as well as
amebic colitis patients in Bangladesh. A total of 98
amebic liver abscess and 28
amebic colitis patients and 43 control subjects were examined. The real-time PCR assay detected E. histolytica
DNA in 49%, 77%, and 69% of blood, urine, and saliva specimens from the
amebic liver abscess patients. For
amebic colitis the sensitivity of the real-time PCR assay for detection of E. histolytica
DNA in blood, urine, and saliva was 36%, 61%, and 64%, respectively. All blood, urine, and saliva samples from control subjects were negative by the real-time PCR assay for E. histolytica
DNA. When the real-time PCR assay results of the urine and saliva specimens were taken together (positive either in urine or saliva), the real-time PCR assay was 97% and 89% sensitive for detection of E. histolytica
DNA in
liver abscess and intestinal
infection, respectively. We conclude that the detection of E. histolytica
DNA in saliva and urine could be used as a diagnostic tool for
amebic liver abscess.