Confirmation In The HBsAg ELISA Grey Zone And Single Reagent Reactive Sample

Objective: To explore the necessity of grey zone set for the results determine by the HBs Ag ELISA assay. And analysis of confirm results in the HBs Ag ELISA grey zone and single reactive sample by neutralization tests.Methods: 295 samples from January 2010 to June 2014 in Bengbu Blood Center were collected. The samples were divided into grey zone group(0.7≤S/CO<1, n=136) and single reagent reaction group(n=159) by double ELISA reagent detection.And neutralization test was performed for HBs Ag confirmation of these samples, and analyze the experimental results by statistical methods.Results: Among 136 grey zone samples, 10 samples showed reactive(7.35%, 10/136)and 14 samples showed abnormal in neutralization test. Among 159 single reagent reaction samples, 19 samples showed positive(11.95%, 19/159) and 16 samples showed abnormal in neutralization test. There were no statistical differences between grey zone and single reagent reactive samples. The positive rates in these groups of S/CO value of 0.70 ~ 0.79, 0.80 ~ 0.89 and 0.90 ~0.99 were respectively 3.92%,5.88% and 14.71%. And there was no statistical significance between the three intervals. The positive rate of double reagent grey zone and single reagent grey zone was respectively 6.35% and 20%, and there was no statistically significant difference.Conclusion: There was reactive in both the HBs Ag grey zone samples and single reagent reactive ones, so great importance should be attached to them. We should combine the actual setting appropriate grey area in laboratory. Verification tests are necessary to reduce the false negative and misdiagnostic frequencies and to ennure the safty of blood transfution.