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Backgroung: Brazil was slow to implement an expanded testing policy for COVID-19, which may have affected the most vulnerable population's access to testing services.Objective: to evaluate the factors associated with performing the molecular test for COVID-19.Methods: cross-sectional study of secondary data from the COVID-19 panel in the state of Espírito Santo. COVID-19 suspicion notification forms were included between September 11, 2020 and March 2, 2021. Hierarchical logistic regression was used to estimate the odds ratio (OR) with 95% confidence interval (CI95%).Results: 419,771 notification forms were analyzed. The prevalence of performing the molecular teste for COVID-19 was 81.1% (CI95% 81.0-81.2). Elderly (OR= 2.70 CI95% 2.56-2.85), health professional (OR=1 .43 CI95% 1.36-1.50), chronic cardiovascular disease (OR=1.13 CI95% 1.09-1.17), diabetes mellitus (OR=1.07 CI95% 1.01- 1.14) and hospitalization (OR=5.95 CI95% 4.53;7.82) were more likely to have undergone the molecular test. Male sex (OR=0.96 CI95% 0.94-0.98), black skin color (OR=0.75 CI95% 0.73-0.78), yellow skin color (OR=0.74 CI95% 0.71-0.77), residing in the northern health region (OR=0.37 CI95% 0.36-0.39) and the homeless population (OR=0.76 CI95% 0.67-0.85) had the lowest chance of having undergone the molecular test.Conclusion: Social, economic, contextual factors and the risk of aggravation of the disease were associated with carrying out the molecular test for COVID-19 in the state of Espírito Santo. Actions are needed to guarantee the access of the most vulnerable population to molecular testing.
Introdução: o Brasil demorou a implementar uma política de testagem ampliada para COVID-19 no qual pode ter afetado o acesso da população mais vulnerável aos serviços de testagem.Objetivo: analisar os fatores associados à realização de testes moleculares para o diagnóstico da COVID-19.Método: estudo transversal de dados secundários do painel COVID-19 do estado do Espírito Santo. Foram incluídas fichas de notificação de suspeita de COVID-19 entre 11 de setembro de 2020 a 02 de março de 2021. Empregou-se regressão logística hierárquica para estimativa de razão de chances (odds ratio, OR) com intervalo de confiança de 95% (IC95%).Resultados: Foram incluídos no estudo 419.771 fichas de notificação. A prevalência da realização do teste molecular para COVID-19 foi 81,1 % (IC95% 81,0%;81,2%). Idosos (OR= 2,70 IC95% 2,56-2,85), profissional da saúde (OR=1,43 IC95% 1,36-1,50), doença cardiovascular crônica (OR=1,13 IC95% 1,09-1,17), diabetes mellitus (OR=1,07 IC95% 1,01-1,14) e hospitalização (OR=5,95 IC95% 4,53;7,82) apresentaram maior chance de ter realizado o teste molecular. Sexo masculino (OR=0,96 IC95% 0,94-0,98), cor da pele preta (OR= 0,75 IC95% 0,73-0,78), cor da pele amarela (OR=0,74 IC95% 0,71-0,77), residir na região norte de saúde (OR=0,37 IC95% 0,36-0,39) e a população em situação de rua (OR=0,76 IC95% 0,67-0,85) apresentaram a menor chance de ter realizado o teste molecular.Conclusão: Fatores sociais, econômicos e o risco de agravamento da doença foram associados a realização do teste molecular para COVID-19 no estado do Espírito Santo. É necessário ações que garantam o acesso da população mais vulnerável ao teste molecular.
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【Objective】 To evaluate the application value of nucleic acid testing (NAT) by studying the NAT-yield of syphilis screening reactive blood from five blood centers. 【Methods】 The blood samples and demographic information of syphilis screening positive donors were collected from five domestic blood centers, i. e. Chongqing, Guangxi, Luoyang, Liuzhou, Mianyang and Urumqi. The treponema pallidum particle agglutination (TPPA) and the established SYBR Green qPCR method were used to analyze the difference between the results of NAT and the other two test results. 【Results】 Among 1 679 reactive blood samples for syphilis screening, 819 were confirmed positive by TPPA, accounting for 49%, with the false positive rate exceeded 50%. As to NAT results, the NAT-yield of syphilis screening reactive samples and confirmed positive samples was the same (both 2.20%); the NAT-yield of TPPA-positive and TPPA-negative samples were 2.20% and 2.74%, respectively. 【Conclusion】 Primary syphilis screening by ELISA has high sensitivity, but also presents high false positive rate. Although TPPA confirmatory test has strong specificity, it cannot reflect the existence of T. pallidum. Therefore, NAT may be used as a supplementary test for syphilis screening so as to more effectively ensure the safety of blood transfusion and blood supply.
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【Objective】 To evaluate the role of anti-HBc detection in current blood screening strategy by the follow-up of repeated donors with antibody to hepatitis B virus core antigen. 【Methods】 Plasma samples were collected randomly from Dalian Blood Center. to test anti-HBc(dual reagents) and anti-HBs via ELISA. The re-donation of eligible donors who were anti-HBc+ and donors reactive to HBV detection were followed up. 【Results】 A total of 1 291 plasma samples were collected randomly from May 2017 to March 2018, among which 405 samples(31.4%)were anti-HBc+. The median age of anti-HBc+ group was observed much higher than that of anti-HBc-group (39 vs 31 years old) (P0.05). Among the 405 anti-HBc+ donors, 3 donors were OBI (0.7%), of which one was screened out in second donation. No HBV DNA was detected out in 3 OBI cases. 【Conclusion】 Although anti-HBc detection is not suitable in blood screening currently, it is of great value in the assessment of blood donor re-entry for HBV reactive donors in blood screening due to the high anti-HBc prevalence among blood donors.
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【Objective】 To analyze the influencing factors of the repeat reactive (RR) rates of minipools implicated in minipool (MP) nucleic acid testing(NAT) in Xiamen Blood Center, in order to provide reference for NAT. 【Methods】 Samples of blood donors from January 1, 2019 to October 31, 2022 were collected in Xiamen Blood Center and tested by MP-NAT(pools of six). Statistical analysis and comparison of MP-NAT RR rates was performed among different years, testers, reagent batches, instrument combinations, CT values of MP-NAT reactive pools and sample backgrounds. 【Results】 A total of 234 715 blood samples were tested by MP-NAT, and 428 pools were reactive, in which 248 pools were individual-donor NAT reactive, with a MP-NAT RR rate of 57.9%. The difference of MP-NAT RR rates were not statistically significant among different years, testers, reagent batches, instrument combinations, and sample backgrounds (P> 0.05). The difference of MP-NAT RR rates among different CT values of MP-NAT reactive pools was statistically significant (χ2=69.587, P<0.05). Significantly abnormal RR rate accurred in two months in 2022, and returned to normal after timely handling. 【Conclusion】 The MP-NAT RR rates is one of the important indicators to monitor the quality of NAT. Once there is a significant change in the MP-NAT RR rates, comprehensive analysis and timely handling should be carried out to ensure the quality of blood detection.
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【Objective】 To retrospectively analyze the serological and nucleic acid testing(NAT) data of voluntary blood donors from six blood banks in Tibet, in order to explore the positive impact of NAT on reducing the risk of infective transfusion in a regional scope. 【Methods】 From 2018 to 2022, 38 718 voluntary blood donors from blood centers of Tibet, Shannan, Shigatse, Naqu, Nyingchi and Ngari were tested for hepatitis B virus surface antigen (HBsAg), hepatitis C virus antibody (anti-HCV), human immunodeficiency virus antigen (HIV) and antibody (Ag/Ab1+2) serological determination by enzyme-linked immunosorbent assay (ELISA). At the same time, Haoyuan and Daan nucleic acid detection systems were used for the combined detection of HBV-DNA, HCV-RNA and HIV-RNA. The results of NAT of reactive ELISA samples were statistically analyzed. 【Results】 A total of 178 ELISA-/NAT+ samples were detected in Tibet over the past five years, including 170 HBV-DNA positive cases, 8 HCV-RNA positive cases, and 0 HIV-RNA positive cases, with the positive rate at 0.460%.The detection rate of 624 ELISA+/NAT+ samples was 1.61%.The age of blood donors with hepatitis B in Shigatse area was slightly higher than that in other areas, and the difference was statistically significant(P<0.05) . 【Conclusion】 The centralized detection of viral nucleic acid in Blood Center of Tibet Autonomous Region can effectively reduce the missed detection of transfusion transmitted diseases and guarantee the blood safety in the region.
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【Objective】 To validate the performance of a nucleic acid testing(NAT) system for blood screening in the high-altitude Nagqu region of Tibet, in order to assess the capability of NAT in high-altitude areas and further enhance blood safety. 【Methods】 Various methods were employed to evaluate the analytical sensitivity, reproducibility, ability to prevent cross-contamination, and comparison between different NAT systems. 【Results】 The NAT system in the Nagqu region of Tibet achieved a 100% detection rate for high-concentration HBV DNA and HIV-1 RNA samples, and over 90% for medium-concentration samples. PROBIT analysis revealed the lower limits of detection (LOD) for HBV DNA and HIV-1 RNA to be 8.29 IU/mL (95% CI, 5.88~20.55 IU/mL) and 40.52 IU/mL (95% CI, 30.26~85.92 IU/mL), respectively. For HCV RNA genotype 2a, the LOD was 97.14 IU/mL (95% CI, 71.00~182.67 IU/mL), all of which were lower than the declared minimum detectable concentrations in the instructions. Reproducibility analysis demonstrated a 100% level of consistency within the system. Cross-contamination performance verification showed a strong ability to resist cross-contamination. Comparative analysis of repeated testing of low-concentration HBV DNA samples and multi-system testing in plain areas revealed consistency rates of 77.78%(14/18) and 77.27%(17/22), respectively, indicating certain differences between the NAT system in Nagqu region and other systems. 【Conclusion】 The NAT system exhibited excellent performance in blood screening at high altitudes. The results of performance validation in high-altitude blood screening NAT systems were largely consistent with those in plain areas, providing a reliable basis for enhancing blood safety in high-altitude regions.
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【Objective】 To analyze the difference of Ct value of HBsAg-/HBV DNA + in blood samples from different types of voluntary blood donors by double ELISA and HBV DNA (MP6) detection, and to investigate the correlation between Ct value and the frequency of repeated blood donation, the first nucleic acid reactivity and the interval time of previous blood donation, so as to provide reference for laboratory evaluation of the effectiveness of nucleic acid testing(NAT) strategy for repeated blood donors occult hepatitis B virus infection(OBI). 【Methods】 The Ct value and information of blood donors from February 2019 to January 2022 in our laboratory were collected. According to the cumulative number of blood donations, they were divided into two groups:first-time blood donor group (Group A) and repeated blood donor group (Group B). Group B was subdivided into Group C 1( twice of blood donation) and group C 2(three or more times of blood donation) according to the cumulative times of blood donation, and Group D 1(< 1 year), Group D 2(1-3 years), Group D 3(3 years or more) according to the first NAT reactivity and the time of previous blood donation, the difference of Ct value and resolution yeild of HBV DNA in each group was compared. The yeild of HBV DNA in two groups was compared by chi-square test, and the difference of Ct values were compared by Nonparametric test. 【Results】 From February 2019 to January 2022, a total of 270 283 blood donors were tested, including 135 695 in Group A and 134 588 in Group B. The yeild of HBV DNA in Group A was 0.150% (203/135 695), which was higher than that in Group B [0.083% (111/134 588)] (P <0.05).All Ct values were non-normal distribution by normal distribution test, and were expressed as median (quartile), the median values of MP6 and resolution Ct were 37.0(35.9,38.2) and 35.5(33.7,36.9) in Group A, 37.2(36.4,38.1) and 36.5(35.5,37.6) in Group B, respectively. Ct values of MP detection and resolution in Group A, of MP detection and resolution in group B, and of resolution in group A and B were all significant (P<0.05) From the cumulative number of blood donations to compare, the median values of MP detection and resolution Ct were 37.5(36.6,38.3) and 36.5(35.4,37.6) in Group C1,37.1(36.4, 37.9) and 36.6(35.6,37.8) in Group C2, respectively. Significant difference in resolution Ct value between Group A and Group C1, Group A and C2 was noticed(P<0.05), the median values of MP detection Ct in D1, D2 and D3 groups were 37.2(36.3,38), 37.1(36.5,37.9), 37.8(36.6.38.9),respectively, with median resolution CT values at 37.0(35.7,37.8), 35.9(34.8,36.9), 36.9(36.1,37.7), respectively. There was a significant difference in the resolution Ct values between between Group A and D1 and D3 groups (P<0.05), and there was a significant difference between the MP detection and resolution Ct values in D2 Group (P<0.05). The resolution Ct values in D2 and D3 Group were lower than those in D1 Group (P<0.05).The interquartile distribution of Ct values in Group A was wider than that in other groups, and the interquartile distribution of Ct values in Group B was more concentrated. Conclusion The Ct value of HBV DNA detected by nucleic acid in blood donors was correlated with different times of blood donation and different intervals of blood donation. The laboratories of blood station should pay attention to the nucleic acid test results of different types of blood donors to ensure blood safety.
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【Objective】 To analyze the SARS-CoV-2 detection results among blood donors in different periods of COVID-19 pandemic control in Shenzhen and assess the antibody levels and infection status of blood donors in different periods, so as to provide reference for subsequent blood testing strategies. 【Methods】 A total of 4 768 plasma samples of blood donors were subjected to pooled testing by nucleic acid testing(NAT) with 8 samples per pool. Additionally, these samples were subjected to a 1000-fold dilution, and the detection of SARS-CoV-2 total antibody was performed by enzyme-linked immunosorbent assay (ELISA). The 4 768 plasma samples were collected from blood donors at different time points in Shenzhen, with inquiries made to determine whether donors during the COVID-19 pandemic were in the convalescence. The antibody positive rates in blood screening samples during different periods of the pandemic and samples from individuals in the convalescence of COVID-19 infection were analyzed. Furthermore, the antibody levels were examined for differences based on gender, age, and blood type. 【Results】 All 4 768 plasma samples from blood donors were negative by NAT, while 2 342 samples were detected positive by the SARS-CoV-2 total antibody detection, with a positive rate of 49.1%. These samples from four periods (September 30 to October 3, 2022; November 3 to 6, 2022; December 27 to 31, 2022; January 6 to 18, 2023) were subjected to a 1 000-fold dilution for COVID-19 antibody detection, and the positive rates were 21.3%, 15.8%, 65.9%, and 93.9%, respectively. 【Conclusion】 The prevalence of COVID-19 antibodies among blood donors in Shenzhen during different periods of the pandemic varied significantly. There was no difference in antibody prevalence among different genders and blood types, while younger individuals exhibited a higher prevalence of antibodies. The risk of COVID-19 transmission through blood transfusion was found to be extremely low.
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@#Objective To prepare the national reference panel of hepatitis B virus(HBV) for nucleic acid testing(NAT)donor screening.Methods A number of plasma samples from donors positive for HBV antibody and patients with HBV infection collected from blood centers,plasma stations and biological products companies in Shanghai,Gansu,Henan,Hunan,Hubei and other regions were tested for HBV DNA viral load agent,and negative and positive reference candidates were screened;The HBV DNA national standard was diluted to 10~3 IU/ml with human negative plasma,as a candidate for limit of detection(LOD).National negative and positive reference candidates of HBV for NAT donor screening and LOD reference to be calibrated were distributed to 8 enterprise laboratories for joint detection of HBVHCVHIV NAT donor screening.The homogeneity and stability of the national reference panel were investigated.Results A total of 8 negative samples with HBV viral load of 0 were screened as negative references and 9 positive samples with viral load of 10~3～10~4 IU/mL were used as positive references;One LOD reference was calibrated with WHO HBV DNA standard,and the virus content was 1.0 × 10~3 IU/ml.The national reference panel showed good stability and the homogeneity inspection met the requirements.Conclusion The national reference panel of HBV DNA for NAT donor screening was prepared,which provided a basis for the quality control and standardization of HBV DNA reagents for donor screening.
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【Objective】 To investigate the situation of hepatitis E virus(HEV) infection among voluntary blood donors in Wuhan area and provide evidences for enhancing blood screening strategies. 【Methods】 HEV nucleic acid detection(NAT) was performed on blood samples from eligible blood donors in Wuhan from November to December 2020. The testing results were analyzed, and the blood donors with repeated reactive results were followed up to clarify the status of infection. 【Results】 Routine screening was performed on 17 409 blood samples from November to December 2020. A total of 17 322 blood samples of eligible blood donors were tested for HEV NAT, and one case of HEV RNA reactivity was detected. The results from the follow-ups showed that the blood donor should be in the window period of HEV seroconversion. The current HEV infection rate of voluntary blood donors in Wuhan arewas 0.058‰(1/17 322), which was lower than other domestic areas. 【Conclusion】 The current HEV infection rate of voluntary blood donors was at a relatively low prevalence level in Wuhan area. Selective blood screening strategies can be taken to further reduce potential risk of blood transfusion infection with hepatitis E virus.
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【Objective】 To investigate the serological and molecular characteristics of HBsAg+ /HBV DNA non-reactive (NR) infections. 【Methods】 Samples tested as HBsAg+ and HBV DNA NR were confirmed by individual NAT repeat testing, viral particle concentration by PEG precipitation combined with in-house nested PCR and real-time quantitative PCR, anti-HBc testing, and HBsAg quantification. HBV sequences were compared with those from donors with chronic and occult infection as controls. 【Results】 A total of 792 195 samples were screened between January 2011 and December 2020, of which 53 (1: 14 947) were confirmed HBsAg+ /HBV DNA NR. HBV DNA was detected further in five (9.4%) samples; three S sequences and four Pre Core/Core sequences were obtained. Unique amino acid substitutions (P130T, P135Q/S, R151Q, G153S and S155F) were found in the Core protein that may affect virus packaging and replication. 【Conclusion】 Extremely low HBV DNA level was detected in plasmas of HBsAg+ /HBV DNA NR donors. Barely detectable HBV DNA might be associated with unusual mutations in the Pre Core/Core protein affecting viral replication. More sensitive HBV DNA and/or HBsAg assays may be considered to further reduce the potential HBV transfusion-transmission residual risk.
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【Objective】 To analyze the difference of circulating threshold (Ct) of polymerase chain reaction (PCR) in blood station laboratories during the external quality assessment, and to put forward suggestions for the quality improvement of participating laboratories. 【Methods】 From 2018 to 2021, the blood station laboratories participated in the external laboratory quality assessment of CITIC including blood screening items with nucleic acid testing method. The data of Roche diagnostic reagent group were used as the source, and the detected Ct values of three groups of quality control samples of HBV A subtype (400 IU/mL), HCV 1b subtype (400 IU/mL) and HIV B genotype (500 IU/mL) were used as the objects. The data were grouped according to quality control (sample) batches, reagent batches and different laboratories. Using the statistical method of variance analysis (assuming P<0.05 as significant), the detected Ct value of each group was analyzed. 【Results】 For the three items (HBV/HCV/HIV), the grouping data involving 42 batches of quality control (13/12/17), 28 batches of reagent (11/8/9) and 57 laboratories (19/19/19) were selected. The grouping analysis of quality assessment batches shows that there was no significant difference between HBV and HCV quality assessment batches, and there was no significant difference between other HIV batches except the two batches of HIV quality assessment samples released in 2021. The grouping analysis of each reagent batch showed that there was no significant difference between each reagent batch for HCV and HIV detection, while there was significant difference between two batches of HBV reagents. After excluding the data groups with significant differences in the quality control batch groups and the reagent batch groups, the detected Ct value of each laboratory group had extremely significant differences in the three items of HBV, HCV and HIV. Through pairing analysis, it was found that four laboratories had significant differences with most other laboratories in the three items, mainly manifested in the high mean value of Ct. 【Conclusion】 For the blood station laboratories with correct test results of quality assessment samples, there are differences in Ct values detected by PCR, which may be mainly caused by the detection ability of the participating laboratories.
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【Objective】 To investigate the related viral markers of HBV DNA reactive samples among voluntary blood donors in Shiyan area, so as to provide some reference for donor re-entry. 【Methods】 From August 2019 to June 2021, 78 samples with HBV DNA reactivity from voluntary blood donors in our blood station were collected, and they were further detected for HBV viral markers(using chemiluminescence assays), nucleic acid testing(NAT) of virus quantification and sequencing analysis. 【Results】 Forty-seven (60.3%)out of 78 HBV DNA reactive samples were from repeated blood donors, and 56.4%(44/78)of them were over 45 years old. Among the five viral markers of hepatitis B, 37.2%(29/78) were positive for anti-HBs alone, 19.2%(15/78) were positive for anti-HBe+ anti-HBc and anti-HBs+ anti-HBe+ anti-HBc, and 11.5% (9/78) were all items negative.A total of 62.8%(49/78) of samples were detected by NAT quantification and seven samples had been successfully sequenced for HBV. 【Conclusion】 NAT can effectively minimize the missed detection of HBsAg methodology and reduce the risk of HBV transmission through blood. The re-entry of HBV DNA reactive blood donors should be treated with care.
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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.
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OBJECTIVE@#To evaluate the risk of reentry in HBV reactive blood donors and feasibility of HBV reentry strategy.@*METHODS@#HBsAg+ or HBV DNA+ donors who had been quarantined for more than 6 months in Jiangsu Province could propose for reentry application. Blood samples were routinely screened by dual-ELISA for HBsAg, anti-HCV, HIV Ab/Ag, and anti- Treponema pallidum and those non-reactive ones were tested by minipool nucleic acid testing (NAT) for three times. To identify occult HBV donors, samples of NAT non-reactive were further tested by electrochemiluminescence immunoassay (ECLIA) for HBV seromarkers (including HBsAg, HBsAb, HBeAg, HBeAb, and HBcAb). Donors of only 4 ECLIA patterns were accepted to reentry, including all 5 HBV seromarkers negative, anti-HBs only but having history of hepatitis B vaccine injection, HBcAb only, HBsAb+ / HBcAb+ with HBsAb more than 200 IU/L. Additionally, the detection rate of HBV infection was compared between routine screening mode and ECLIA, as well as the reentry qualified rate of HBsAg+ and HBV DNA+ blood donors.@*RESULTS@#From Oct. 2016 to Aug. 2019, a total of 737 HBV reactive donors had applied for reentry, including 667 HBsAg+ reactive and 70 HBV DNA+ reactive donors. Among 3 screening methods, the highest HBV detection rate (43.15%, 318/737) was observed on ECLIA, while only 4.75% (35/737) on ELISA and 3.12% (23/737) on NAT, respectively. Among 4 qualified patterns of HBV serological markers, the highest proportion was found in the all negative group (22.90%, 155/677), followed by the group with HBsAb+ only and history of hepatitis B vaccine injection (19.35%, 131/677), and the median concentration of HBsAb was 237.7 IU/L. The unqualified rate of HBV DNA+ donors was 82.86%, which was significantly higher than 47.98% of HBsAg+ donors.@*CONCLUSION@#Routine screening tests merely based on ELISA and NAT could miss occult HBV donors and may not be sufficient for blood safety. HBsAb concentration and vaccine injection history should be included in the evaluation of HBV reactive donors who intend to apply for reentry. There is a relatively larger residual risk of occult HBV infection in blood donors quarantined for HBV DNA reactive.
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Humans , Blood Donors , DNA, Viral , Hepatitis B , Hepatitis B Surface Antigens , Hepatitis B virus/geneticsABSTRACT
Because of the low throughput of current first-generation sequencing and the shortread length of second-generation sequencing, a new technology that overcomes the above shortcomings has emerged. The third-generation sequencing based on nanopore does not rely on the chain reaction of DNA polymerases and distinguishes bases by identifying electrical signals. It has broad application prospects and also faces more challenges. At present, it has many applications in detection of infectious pathogens, infectious disease prevention and control, genetic variation, and tumor diagnosis.
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OBJECTIVE@#To observe the clinical characteristics of mild and common COVID-19 patients infected with the Omicron variant, and to analyze related factors affecting the time to negative conversion of viral nucleic acid detection.@*METHODS@#Clinical data of 1781 patients with coronavirus disease 2019 (COVID-19) admitted to a cabin hospital in Shanghai from April 12 to May 26, 2022, were retrospectively analyzed, including age, gender, height, weight, clinical symptoms, comorbid diseases, COVID-19 vaccination, treatment, and nucleic acid negative conversion time. Univariate and multivariate logistic regression analyses were used to analyze the influencing factors of nucleic acid negative conversion time.@*RESULTS@#Among the 1781 patients, 995 were male and 786 were female, with a median age of 39 (30, 52) years. There were 727 patients (40.8%) with overweight and obesity [body mass index (BMI) > 24 kg/cm 2) and 413 patients (23.2%) had comorbid diseases. 205 cases (11.5%) were not vaccinated while 1576 cases were vaccinated. There were 1233 cases (69.2%) with one or more symptoms. The main clinical symptoms were cough (60.3%), expectoration (50.4%) and fever (36.9%). 1444 cases (81.0%) were treated with Chinese medicine, 78 cases (4.4%) were treated with western medicine, 14 cases (0.8%) were treated with integrated Chinese and western medicine, and 245 cases (13.8%) did not receive any medical treatment. All patients improved and were discharged. The median nucleic acid negative conversion time was 10.3 (7.4, 12.4) d. Univariate and multivariate analysis showed that, age ≥ 60 years ( OR＝1.537, 95% CI: 1.116 - 2.115, P<0.01), BMI > 24 kg/cm 2 ( OR＝1.344, 95% CI: 1.106 - 1.634, P<0.01 ) and hypertension ( OR＝1.518, 95% CI: 1.094 - 2.106, P<0.05) were independent risk factors for prolonged nucleic acid negative conversion. COVID-19 vaccination ( OR=0.548, 95% CI: 0.398 - 0.755, P<0.01) was a protective factor, that is, vaccination shortened the time for the nucleic acid test to become negative.@*CONCLUSIONS@#The symptoms of the Omicron variant infection were relatively mild and occult. Age ≥ 60 years old, comorbid hypertension, no vaccination and BMI > 24 kg/cm 2 are independent influencing factors for prolonged nucleic acid negative conversion.
Subject(s)
Humans , Female , Male , Middle Aged , SARS-CoV-2 , COVID-19/epidemiology , COVID-19 Vaccines , Retrospective Studies , China , Hypertension/epidemiology , Nucleic AcidsABSTRACT
Resumen Introducción: La pandemia de COVID-19 ha afectado a millones de personas en todo el mundo. La identificación de sujetos infectados ha sido importante para el control. Objetivo: Evaluar el rendimiento de una reacción de polimerasa en cadena (RPC) cuantitativa en tiempo real (en inglés: RT-qPCR) para SARS-CoV-2, utilizando saliva como matriz en comparación con un hisopado nasofaríngeo (HNF). Metodología: Se reclutaron adultos en atención ambulatoria, la mayoría sintomáticos. Fueron estudiadas 530 muestras pareadas de saliva e HNF con RT-qPCR. Resultados: Fueron positivas 59 muestras de HNF y 54 de saliva. La sensibilidad con saliva fue 91%, especificidad 100%, el valor predictor positivo (VPP) 100%, valor predictor negativo (VPN) 98%. El índice Kappa fue de 0,95 y LR-0,08. En promedio, el umbral de ciclo (en inglés cycle threshold-CT) de la saliva fue 3,99 puntos más alto que los de HNF (p < 0,0001) mostrando que la carga viral (CV) es menor en saliva. La carga viral en ambas disminuyó con el tiempo después del inicio de los síntomas. El muestreo de saliva fue preferido por los sujetos en lugar de HNF. Conclusión: Este estudio demuestra que la RPC para SARS-CoV-2 utilizando saliva, es adecuada para el diagnóstico de COVID-19 en adultos ambulatorios, especialmente en la etapa temprana de los síntomas.
Abstract Background: The COVID-19 pandemic has affected millions of people around the world. Part of control strategies is testing a large proportion of the population to identify and isolate the infected subjects. Aim: To evaluate the SARS-CoV-2 detection by the performance of a reverse transcription and quantitative polymerase chain reaction (RT-qPCR) against SARS-CoV-2, using saliva as a matrix compared to a nasopharyngeal swab (NPS) to simplify obtaining a diagnostic sample. Methods: Adults in outpatient care were recruited, 95% of them symptomatic. We studied 530 paired saliva and NPS samples by SARS-CoV-2 RT-qPCR. Results: Fifty-nine individuals tested positive in NPS and 54 in saliva samples. Sensitivity for saliva sample was 91%, specificity 100%, positive predictive value (PPV) 100%, negative predictive value (NPV) 98%. The Kappa index was 0.95 and LR-0.08. On average, the cycle threshold (CT) of saliva was 3.99 points higher than those of NPS (p < 0.0001) showing that viral load (VL) is lower in saliva than in NPS. Viral load in both decreased over the time after onset of symptoms. Saliva sampling was preferred by subjects instead of NPS. Conclusion: This study demonstrates that SARS-CoV-2 RT-qPCR using saliva, even with lower VL, is suitable for the diagnosis of COVID-19 in outpatient adults, especially at early stage of symptoms.
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【Objective】 To verify the key performance parameters of Roche Cobas S201 multiplex NAT for blood donors, so as to provide data for the conformation of multiplex NAT performance and establish a scientific and feasible verification scheme. 【Methods】 Comprehensive performance verification on four key parameters of ROCHE COBAS S201 multiplex NAT system, including the 95% detection limit, compliance rate, anti-interference ability and operator comparison were conducted. The data were compared with the specifications provided by the manufacturer to evaluate the performance of laboratory testing system and ensure the quality of blood testing. 【Results】 2 sets of COBAS S201 multiplex NAT system in our laboratory were used to perform 5 times of the 95% detection limit value declared by the manufacturer for individual tests. The experimental results showed that the target NAT can be detected 100% and the lower limit of determination was verified. Single-virus NAT was performed to detect 5 different HBV DNA concentrations (25 ~400 IU/mL), 5 different HCV RNA concentrations (25 ~400 IU/mL), 5 different HIV RNA Concentration (100~1 000 IU/mL), and 5 negative tubes. The experimental results showed that all detected values of 20 tubes were 100% consistent with the true value, and the performance parameter "coincidence rate" was verified. Samples containing lipoemia, hemolysis, with ALT>50 mL/L and syphilis-positive endogenous interfering substances with 3 times of the 95% detection limit value were tested for 3 times, and results showed both response rate (3/3) and yielding rate reached 100%. In the control group (with none or in the normal range of interfering substances), reactivity was detected in samples with extremely low concentration of 3 times of the 95% detection limit, showing no significant difference (P>0.05). Above results fully showed that the existence of interference substances (lipidemia, hemolysis, ALT ≥ 50 and syphilis positive) in the blood of donors had no significant effect on the yielding of HBV/HCV/HIV virus target nucleic acids. Different operators performed the sample loading tests with same instrument, reagent and specimen showed 100% consistency in the results. It could be preliminarily assessed that there was no difference in the operations between the operators in this verification. 【Conclusion】 The verification scheme of the multiplex NAT system for methodology performance index (95% detection limit, coincidence rate, anti-interference ability, and operator comparison) established in this study, showed simple, flexible, scientific and feasible characteristics and could provide reference and data support for domestic blood transfusion services in acid detection.
ABSTRACT
【Objective】 To compare the results by minipool and individual NAT on blood samples with HBsAg detection S/CO value between 0.25-0.90 by ELISA, in order to re-evaluate the safety of NAT for such negative samples with high HBsAg S/CO value and provide references for the optimization of detection process. 【Methods】 A total of 30 blood samples which were non-reactive for HBsAg by ELISA twice and with the S/CO value of any reagent between 0.25-0.90 (defined as " high S/CO value negative" ) from our center from February to October 2020 were collected, and minipool test of 6 samples and individual test were performed in parallel. 11 samples which were negative by minipool tests but positive by individual test were submitted to repeated NAT minipool tests, and the results of each test were recorded and analyzed. 【Results】 The median S/CO values of the 30 samples by two ELISA reagents were 0.565 and 0.320, respectively, and the differences were statistically significant (P 0.05). 【Conclusion】 The NAT-yield of samples with high ELISA HBsAg S/CO value was high in individual test and low in minipool test, and the NAT-yield in minipool test could be improved by repetitive test. Therefore, the safety of NAT for samples with high HBsAg S/CO value should be re-evaluated as minipool test is dominant in blood stations. Individual NAT test is recommended for such samples currently as there is no any other more sensitive detection approaches.