Comparative study about CMIA and two kinds of ELISA on low level of HBsAg samples

Objective To compare the sensitivity between China-made one-step hepatitis B surface antigen(HBsAg) enzyme linked immunosorbent assay(ELISA) reagent and two-step HBsAg ELISA reagent supplied by same company.Methods HBsAg samples were detected by one-step ELISA and two-step ELISA,at the same time compared with the result tested by CMIA.Results In 90 cases,the results of one-step ELISA and two-step ELISA were all negative while CMIA were negative.Among 61 low level samples detected by CMIA,15 positive samples were detected by one-step ELISA,46 positive samples were detected by two-step ELISA.The sensitivity of two-step ELISA was significantly higher than that of one-step ELISA(P0.01).One-step ELISA had the same sensitivity of detection with CMIA above 2.50 U/mL.Two-step ELISA had the same sensitivity of detection with CMIA above 0.50 U/mL.The sensitivity of two-step ELISA was significantly lower than CMIA under 0.50 U/mL(P0.01).Conclusion The sensitivity of two-step ELISA is significantly higher than one-step ELISA,but is still less than CMIA in the lower level samples.