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.

Objective:To analyze the situation of hepatitis B enzyme immunoassay-positive but nucleic acid negative infection (HBsAg ELISA(+ )/HBV-DNA(-)) among unpaid blood donors in Zhejiang Blood Center, and to explore the causes of inconsistency between enzyme immunoassay and nucleic acid result.Methods:A single nucleic acid test was performed on blood donors whose routine blood screening result were HBsAg-ELISA(+ )/HBV-DNA(-), and the test result of such blood donors were analyzed.Results:A total of 205 HBsAg-ELISA(+ )/HBV-DNA(-) samples were screened from 114017 blood donors from May to November, 2022. The proportion of male blood donors (0.14%) were significantly lower than that of the female blood donors (0.24%)( χ2= 14.761, P<0.005); the proportion of the first blood donor (0.32%) was significantly higher than that of the second blood donor (0.09%) ( χ2 = 78.781, P<0.005); the difference between different education levels is statistically significant ( χ2 =47.753, P<0.005). After single-person nucleic acid re-detection, the re-detection rate of nucleic acid in ELISA double-reagent positive samples was higher than that in single-reagent positive samples ( χ2=94.378, P<0.005); there was no significant difference between ELISA reagent 1 and reagent 2 in the detection rate of nucleic acid ( χ2 =0.163, P>0.005). There was no significant difference in the positive rate of secondary nucleic acid detection between the two nucleic acid detection systems ( χ2=0.626, P>0.005). Serological supplementary test showed that 11 HBV-DNA(+ ) samples showed two serological combination patterns after chemiluminescence detection, namely HBsAg(+ )/HBeAb(+ ) and HBeAb(+ ), most of which were HBsAg(+ )/HBeAb (+ ), a total of 10 cases, accounting for 90.91%, and only one case was HBeAb (+ ), accounting for 9.09%. The quantitative result of HBsAg showed that most of them were at low HBsAg level. Conclusions:After re-detection by single nucleic acid detection method, HBsAg-ELISA(+ )/HBV-DNA(-) samples of blood donors do have a certain proportion of HBV-DNA(+ ), but most of the samples were still HBV-DNA (-), additional experiments on HBV serological markers and HBV-DNA are needed to determine their true infection status and clarify the reasons for the inconsistency between enzyme immunoassay and nucleic acid test result. In addition, nucleic acid and HBsAg detection reagents with high sensitivity and specificity should be selected as far as possible in blood donor screening to ensure the accuracy of result.

[Objective] To investigate the infection and characteristics of hepatitis E virus among blood donors in Hangzhou. [Methods] A total of 5 075 blood samples of blood donors from Zhejiang Provincial Blood Center from September to November 2023 were collected, including 5 037 samples with normal ALT and 38 samples with elevated ALT (>50 U/L). Enzyme-linked immunosorbent assay (ELISA) was used to detect anti-HEV IgM, anti-HEV IgG and HEV-Ag. The Fisher test and Chi-square test were used to evaluate the difference in the reactivity rates of anti-HEV IgM and anti-HEV IgG among different levels of ALT. The distribution characteristics of HEV screening in blood donors were analyzed. Univariate and multivariate logistic regression were used to analyze the susceptibility factors of anti-HEV IgM and anti-HEV IgG seropositivity, and the anti-HEV IgM-reactive blood donors were followed up by telephone. [Results] The reactivity rates of anti-HEV IgM, anti-HEV IgG and HEV-Ag in 5 075 blood samples were 0.45%, 22.98% and 0%, respectively. There was no difference in the reactivity rates of anti-HEV IgM and anti-HEV IgG among different levels of ALT (P>0.05), and the results of univariate and multivariate logistic regression analysis showed that age was a risk factor for anti-HEV IgM and anti-HEV IgG reactivity in blood donors (P<0.05), while no difference in the reactivity rates of anti-HEV IgM and anti-HEV IgG among blood donors was noticed in gender, occupation and education level (P>0.05). [Conclusion] There is a potential risk of transfusion-transmitted HEV (TT-HEV) in Hangzhou, and a cost-effective HEV screening strategy needs to be established to continue regular HEV surveillance in Hangzhou to assess the risk of infection.

Objective To understand the status of HIV infection among unpaid blood donors in Hangzhou,and to provide data support for reducing the risk of HIV transmission through blood transfusion,and formulating effective blood donor recruitment and AIDS prevention and control strategies in Hangzhou.Methods Enzyme-linked immunosorbent assay(ELISA)and nucleic acid testing(NAT)were used to detect HIV-I/Ⅱ antibody/antigen and HIV RNA from 902 847 unpaid blood donors in Hangzhou from January 2016 to December 2020.Anti-HIV antibody/antigen or HIV RNA reactive samples were sent to Hangzhou Center for Disease Control(CDC)for further confirmation by Western bloting and NAT.Results A total of 103 HIV positive cases were detected in Hangzhou area from January 2016 to December 2020,with a positive detection rate of 0.01%,101 cases were positive for ELISA and NAT screening,2 cases were negative for ELISA screening and positive for NAT.Among the 103 infected patients,males(91.26%,94/103),18-35 years old(69.90%,72/103),and first-time blood donors(68.93%,71/103)were the majority.The positive rate of HIV among blood donors decreased year by year from 2016 to 2020(χ2=7.181,P=0.007),but there was no significant difference in HIV positive rate between male and female blood donors(χ2=10.336,P=0.350;χ2=0.653,P=0.957).There was no significant difference in HIV positive rate among blood donors of different age groups(χ2=6.378,P=0.173;χ2=2.318,P=0.678;χ2=5.284,P=0.259;χ2=9.183,P=0.057).Conclusion In recent 5 years,HIV infection has been at a low epidemic level among unpaid blood donors in Hangzhou,but there is still an infection risk.It is necessary to strengthen the recruitment of blood donors from low-risk groups,adopt advanced detection technology and select appropriate detection strategies to ensure blood safety.