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【Objective】 To analyze the reasons for the invalidity of blood nucleic acid test results, and to explore the countermeasures to reduce the invalidity of the test. 【Methods】 From 2019 to 2021, the number of tests performed in our laboratory for Cobas s201 blood nucleic acid screening system and the number of batches and tests with invalid results were counted, and the types and reasons of invalid results were analyzed. 【Results】 From 2019 to 2021, the Cobas s201 nucleic acid detection system detected a total of 5, 420 batches and 127, 950 pools, and the invalid rate of batches and pools were 1.83% and 1.97%, respectively. The types of invalid results can be summarized as improper operation, sample quality problems, invalid quality control (IQC), equipment failure and others. Among them, IQC and equipment failure were the main reasons for invalid results, accounting for 44.51% and 39.96%, respectively. IQC was mainly related to cross-contamination of samples and insufficient mixing of quality control products. Equipment failures mostly occurred in the robotic arm gripper of the nucleic acid extraction instrument and the TC module of the amplification instrument. 【Conclusion】 The laboratory should conduct quality monitoring for invalid results, and take targeted improvement measures, especially to reduce invalid results caused by invalid quality control and instrument failure.
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【Objective】 To retrospectively analyze the unqualified blood screening results of voluntary blood donors in Guangzhou area during 2016~2020, and analyze various factors that affect the blood screening results, for the purpose of providing a scientific basis for recruitment and retention of blood donors, improving blood safety, and avoiding waste of blood resources. 【Methods】 A total of 1 548 204 voluntary blood donors in Guangzhou from 2016 to 2020 were selected as the research objects, and the blood samples were screened by dual ELISA and once NAT. The unqualified rate of different years and populations were counted and the analysis of risks of unqualified blood testing was performed by conditional Logistics regression. 【Results】 An overall unqualified rate of blood screening was 2.52% in Guangzhou from 2016 to 2020, the unqualified rate of every year showed a downward trend first and then an upward trend. HBsAg and ALT were the two primary deferral causes, the positive rate was 0.65%(10 129/1 548 204) and 1.22%(18 824/1 548 204), respectively; the unqualified rate in male blood donors3.10%(31 091/1 004 079) was significantly higher than that in female(P<0.05), and that in blood donors aged 18~25 was 1.84%(12 781/694 374), which was lower than the other three age groups (P<0.05). Fewer students(1.33%, 4 024/302 007) and bachelor degree donors(1.57%, 5 379/341 662) were deferred. Compared with individual blood donors, group blood donors’ deferral rate(2.62%, 21 307/813 664) was higher. The deferral rate of first-time blood donors(4.57%, 24 469/535 551) were higher than the repeated blood donors (P<0.05) , meanwhile, whole blood donors(2.84%, 38 111/1 340 678) higher than those apheresis donors (P<0.05). Gender, age, occupation, education, frequency and blood components donated were risk factors for unqualified blood screening. 【Conclusion】 The deferral rates of voluntary blood donors in Guangzhou showed an overall upward trend, from 2016 to 2022. HBsAg and ALT were the primary deferral causes, and there were differences in demographics and blood donation characteristics. To formulate targeted recruitment strategies according to the test results of voluntary blood donors, and strengthen the publicity of low-risk groups and the consultation and screening before blood donation, will be a great benefit for reducing the blood scrap and guaranteeing the blood safety.
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【Objective】 To assess the trend of hepatitis B virus (HBV) prevalence and associated risk factors among voluntary blood donors in Guangzhou area from 2011 to 2020, and to explore the impact of hepatitis B vaccination in neonates on the risk of HBV infection. 【Methods】 Blood samples of 2 624 434 voluntary blood donors from 2011 to 2020 in Guangzhou were tested by HBV surface antigen (HBsAg) enzyme-linked immunosorbent assay (ELISA) reagents twice and nucleic acid test (NAT) reagent once. Samples reactive to ELISA twice, or ELISA once + NAT were considered as HBV infection. The gender, age, ethnicity and region of HBV infected blood donors were collected, and the incidence of HBV infection in blood donors born before and after 1992 (when HBV vaccination was conducted in neonates) was compared. The trend and risk factors of HBV infection in blood donors in Guangzhou from 2011 to 2020 were analyzed. 【Results】 An overall HBV prevalence of 0.75% was found in voluntary blood donors in Guangzhou area from 2010 to 2020, showing an overall downward trend(P0.05), but both were significantly higher than that in Hong Kong, Macao, Taiwan and foreign countries (P<0.05). HBV prevalence in Han nationality donors was significantly higher than the ethnic minority donors (P<0.05). Gender, age, ethnicity and birth vaccination are the main risk factors for HBV infection among blood donors. 【Conclusion】 The overall HBV prevalence among voluntary blood donors in Guangzhou area from 2011 to 2020 has shown a decreasing trend, and differences have been found in gender, age, region, ethnicity and birth vaccination, which is helpful to formulate targeted recruitment strategies, thus reducing the risk of transfusion transmitted HBV.
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Objective To investigate the situation and distribution of human parvovirus B19(HPV B19) infection in volunteer blood donors in Guangzhou.Methods Blood samples from volunteer blood donors were tested for HPV B19 IgG and IgM antibody by ELISA.Real-time PCR assay was applied to detect HPV B19 DNA of HPV B19 IgG and /or IgM antibody positive specimens.Results The prevalence of HPV B19 IgG and IgM antibodies were 38.6%(679/1760) and 1.9%(33/1760) respectively,among volunteer blood donors,and there was significant difference between them((P
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Objective To investigate the situation and distribution of Severe Acute Respiratory Syndrome coronavirus (SARS-CoV) infection in volunteer blood donors during SARS epidemic phase and non-SARS epidemic phase in Guangzhou and provide scientific basis for developing preventive strategies. Methods Blood samples from volunteer donors were tested for SARS-CoV Ab by ELISA,and samples from 31 plasma donors recovered from SARS were tested as control. Donors with positive SARS-CoV Ab were further tested for SARS-CoV RNA by fluorescent polymerase chain reaction. Standardized questionnaires were adopted to conduct investigation by telephone on 20 donors with positive SARS-CoV Ab. Results SARS-CoV Ab was positive in 56 of 6120 volunteer blood donors and in 30 of 31 plasma donors recovered from SARS. The positive rates of SARS-CoV Ab were 0.92% and 96.77% respectively. In volunteer blood donors of SARS epidemic phase and non-SARS epidemic phase, the positive rates of SARS-CoV Ab were 0.91% and 0.92% respectively, and there was no significant difference between them. The mean S/CO and the titer of SARS-CoV Ab were 2.34 and ≤1∶2 respectively in the 56 volunteer blood donors, significantly lower than those of the 30 plasma donors recovered from SARS (S/CO 14.8,titer ≤1∶32). All donors with positive SARS-CoV Ab were negative for SARS-CoV RNA. Telephone consultation of 20 random blood donors with positive SARS-CoV Ab found that they were in good health and had not have close contact with SARS patients. Conclusion There is a low positive rate of SARS-CoV Ab among random blood donors in Guangzhou. Further studies are needed to find out whether those donors have been infected by SARS. It is also possible that those reactions were false positive, which might be caused by cross reactions. It is suggested that the present measures of SARS prevention could ensure blood safety.