[Immunodiagnosis of human clonorchiasis by a micro-enzyme-linked immunosorbent assay]

A micro-enzyme-linked immunosorbent assay (ELISA) utilizing antigen from lyophilized Clonorchis sinensis adult worms extracted with triethanolamine buffered saline (TBS), veronal buffered saline (VBS) or phosphate buffered saline (PBS) were used to test 66, 31 and 9 sera from clonorchiasis patients, uninfected normal humen and patients with other parasitic infections, respectively. Four different combinations of incubation time between serum with antigen and serum with conjugate at either 37 degrees C or room temperature were tried. The combination of 6 hours and 16 hours reaction time processed at room temperature with shaking was chosen in this study because it revealed no pseudo-negative and cross reactions with high sensitivity, specificity and predictive value. There were no statistic difference among mean optical densities in micro-ELISA reactions of 66 sera (in 800 X dilution) from clonorchiasis patients with TBS, VBS or PBS antigen, respectively, but results obtained from TBS antigen seemed better than other two antigens. Good correlation was observed between the antibody titer or ELISA readings of sera form clonorchiasis patients and their worm burden expressed as eggs per gram of feces (EPG).