Analysis for Reasons about HBsAg False Negative in ELISA One-step Sandwich Assay

Objective:To investigate the reasons for HBsAg false negative in ELISA one-step sandwich assay.Methods:Serum samples with HBeAg(+),HBcAb(+)and HBsAg(-)in ELISA one-step sandwich assay were screened,then HBsAg was detected in these samples with ELISA two-step sandwich assay,multiproportion-dilution ELISA one-step sandwich assay,as well as chemiluminescence immune quantitative assay.Results:Out of 112 166 serum samples,9 samples were found with HBeAg(+),HBcAb(+)and HBsAg(-)in ELISA one-step sandwich assay,with a portion of 0.008%;Out of these 9 samples,only 1 showed positive in ELISA two-step sandwich assay,at the same time using multiproportion-dilution ELISA one-step sandwich assay,the same one turns positive at 1∶327 68 dilution,with a quantitative HBsAg250 IU/mL,obviously it belonged to HD-HOOK.In other 8 samples which showed negative in both ELISA two-step sandwich assay and multiproportion-dilution ELISA one-step sandwich assay,1 was with a quantitative HBsAg=144.41 IU/mL,and 7 with a quantitative HBsAg from 0.05 to 5 IU/mL.Conclusion:In ELISA one-step sandwich assay,false negative in high-dose HBsAg exactly exists,but it seems more serious in low-dose ones.We suggest using kits and methods with higher sensitivity,and probably in the future both the users and the kits'manufacturers should pay more attention to false negative in middle-dose ones.