Objective To analyze the reasons of invalid detections occurred in using three kinds of nucleic acid detection systems in our laboratory since 2016.Methods Analyze the numbers and types of invalid detections,for Roche Cobas S201 system from January to December 2016,Procleix Tigris system from January to September 2016,and Procleix Panther system from September 2016 to March 2017,respectively.Results The invalidation rates of Cobas s201,Tigris,and Panther systems were 0.90％ (402/44 838),4.01％ (2 960/73 835),and 1.34％ (1 093/81 741),respectively,and there were statistically significant differences between the three detection systems (P＜0.05).Except for the differences between Roche Cobas s201 and Panther 1404,there were statistically significant differences between instruments (P＜0.05).Failure of instruments,invalid detection of reagent calibrators,fault operation and sample quality are the causes of invalid detection.Conelusion The main reason of invalidation is instrument failure and reagent calibrator failmre.Invalid detections of nucleic acid screening is related on different detection systems.

Objective : To investigate the prevalence of hepatitis B virus ( HBV ) infection among volunteer blood donors in Hangzhou City, and to evaluate the residual risk of transfusion-transmitted HBV infections. Methods : Data pertaining to volunteer blood donors in Hangzhou City from 2016 to 2019 were retrieved from the blood donor management system. Hepatitis B surface antigen ( HBsAg ) was detected by enzyme-linked immunosorbent assay ( ELISA ) and HBV DNA was detected using nucleic acid testing. The incidence/window period model was employed to assess the residual risk of HBV transmitted through transfusion from donors. Results : The prevalence of HBV infections was 0.56% among the 320 755 first-time donors and 0.13% among the 279 816 repeat donors in Hangzhou City from 2016 to 2019, and a higher prevalence of HBV infection was detected among first-time donors than among repeat donors ( P<0.05 ). The residual risks of transfusion-transmitted HBV infection were 296.38 per million person-times ( 95%CI: 277.57 to 315.19 per million person-times ) and 98.79 per million person-times ( 95%CI: 87.15 to 110.43 per million person-times ) among first-time and repeat donors with positive HBsAg, and were 86.79 per million person-times ( 95%CI: 76.60 to 96.98 per million person-times ) and 28.93 per million person-times ( 95%CI: 22.63 to 35.23 per million person-times ) among first-time and repeat donors tested positive for HBV DNA, respectively. Conclusions There is still a residual risk of HBV infection transmitted through transfusion from blood donors in Hangzhou City. Nucleic acid testing may remarkably reduce the residual risk of transfusion-transmitted HBV infection in blood donors.