Assessment of validity of counterimmunoelectrophoresis and ELISA in the routine diagnosis of amoebiasis.

Counterimmunoelectrophoresis (CIE) was used to detect antibodies against Entamoeba histolytica in 99 sera from amoebiasis suspected patients using antigens from the HK-9 and HT-12 strains of axenically cultivated E. histolytica. There was no significant difference of seropositive rates using antigens from these two strains suggesting the both strains were equally suitable for use in the routine CIE test for the diagnosis of amoebiasis. In comparison with ELISA, the CIE test was a little less sensitive than ELISA with per cent sensitivity of 93.5 and 100 respectively. Two amoebic liver abscess patients who were CIE negative were ELISA positive. The CIE seropositive rate was related to the period after onset of clinical symptoms with per cent positivity of 66.7, 93.3 and 100 when the sera were tested on less than or equal to 5, 6-10 and greater than or equal to 11 days of illnesses respectively.