Abstract:

Objective  To evaluate the feasibility of a new diluent as a substitute for the original ones (saline used for diluting the lyophilized sensitized red cells, and distilled water for diluting the serum specimen) packaged in the commercial indirect hemagglutination (IHA)assay kit manufactured by Anhui Anji Pharmaceutical Technology Co., Ltd. Methods  Phosphate buffered solution(PBS, pH7.2)was used to replace the diluent in the original kit, and two preparations were compared regarding the sensitivity and specificity in detection of Schistosoma japonicum as well as the cross-reactivity with liver fluke, lung fluke, giant intestinal fluke and hookworm. The minimal quantification and the agglutination pattern in each group were also observed. Results  The sensitivity and specificity were 95% and 96.9% for the modified kit, 94.2% and 95.8% for the original one, which suggested no significant difference(χ2=0.000, P=1.000). The Youden index were 0.92 and 0.9, respectively, and the minimum detectable amount was equal 1:1 280 to the two kits. However, PBS led to favorable agglutination pattern. The cross-reactivity rate with liver fluke, giant intestinal fluke and hookworm  was 0 and 19.4% with the lung fluke. Conclusion  It is feasible to replace the diluent in original kit with PBS as dilution for the modified IHA kit.

Key words: Schistosoma japonicum, IHA, Diluent