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【Objective】 To analyze the results of different methods for reactive samples screened by the enzyme linked immunosorbent assay (ELISA) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in blood donors. 【Methods】 From March to April 2020, a total of 8 632 blood samples in Shenzhen were screened for SARS-CoV-2 total antibodies (TAb, including IgG, IgM, IgA) in plasma using ELISA(PC group), the antibody reactivity samples and their follow up plasma samples (FC group), and samples of disease control group(DC group) from January to April 2020 were detected using the following methods: 1) ELISA method for detecting IgG, IgM, and (or without detection) TAb; 2) pseudovirus neutralizing antibody test(pVNT); 3) western blot (WB) of SARS-CoV-2 antibody. The negative control group(NC group) from February to April 2020 performed ELISA and WB testing. 【Results】 Among the 34 total antibody positive samples, 2 were positive for pVNT test, and the total antibody, IgG and WB in the initial screening and tracking testing were positive. Thereafter, it was determined to be confirmed positive. The other 2 cases were positive for pVNT test, while the samples with positive WB results were in the follow-up stage. The TAb, IgG, and pVNT results did not conform to the dynamic evolution of antibodies, and cannot be determined as confirmed positive. 【Conclusion】 The infection status of antibody reactivity samples screened by SARS-CoV-2 ELISA can be judged by the logic of pVNT, WB and the dynamic change of antibody.
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Objective To analyze the positive results of HIV antibody screening in the laboratory of AIDS confirmation center of Hubei Provincial Center for Disease Control and Prevention from 2014 to 2020, and to provide a basis for improving detection strategies. Methods A total of 2 728 primary screening positive specimens received by the laboratory of Hubei confirmation center from 2014 to 2020 were retested with two reagents. Specimens with at least one reactive result were confirmed with western blot (WB). The samples with uncertain or negative WB results were further confirmed by nucleic acid quantitative detection. The test results were analyzed retrospectively. Results A total of 2 297 specimens with positive retest results were confirmed by WB, with a positive rate of 93.47%. The highest proportion of patients was from medical institutions. The positive rate detected by 4 diagnostic kits was apparently higher in S/CO＞10 cases than that in S/CO≤10, and the difference was statistically significant (P 5 000cps / ml, and 12 cases were TND. 13 of the 30 WB negative samples had nucleic acid test results＞5 000CPs/mL . Conclusions The coverage of HIV screening laboratories in hospitals at all levels should be further increased to find more HIV infected persons. The anti-HIV ELISA S/CO ratio is correlated with the positive results confirmed by western blot. Therefore, ELISA S/CO ratio can be used to predict anti-HIV antibody positivity. For samples with uncertain or negative WB detection, supplemental nucleic acid test should be carried out timely for early diagnosis.
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Objective To compare the differences of two kinds of EIA reagents for HIV-1/2 (Ab/Ag) screening results of voluntary blood donors,in addition to find out the feasibility of reducing 1 times of EIA detection.Methods To collect data of HIV 1/2 screening positive results and confirmatory test for voluntary blood donors from 2009 to 2014 in Jiaxing area,and to compare the relationship of screeing test results with that of the confirmatory test,and then to analyze the relevance between S/CO values of screening test and confirmatory test.Results Screening positive rates of domestic and imported reagents,which were 9.58/10 000 and 12.43/10 000,respectively;and the confirmatory coincidence rates were 11.84％ and 9.12％,respectively.There was no significant difference (x2 =1.11,P＞0.05).The double-reagent joint detection positive rate was 1.37/10 000,and its positive predictive value was 82.86％.Single-reagent test result compared with that of double-reagent test,which had significant differences (x2domestic =94.04,P＜0.05 and x2ximported =124.86,P＜0.05).When the S/CO value was more than 6,domestic and imported reagents positive predictive values were 93.55％ (29/31) and 87.50％ (28/32),respectively.Conclusion There is no difference between domestic and imported reagents EIA-HIV1/2.
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O Brasil é o país com o maior número de pessoas infectadas pelos vírus linfotrópicos de células T humanas dos tipos 1e -2 (HTLV-1 e HTLV2) com mais de 2,5 milhões de indivíduos infectados. Em 1993, a realização de testes sorológicos específicos tornou-se obrigatória em Bancos de Sangue. O HTLV-1 causa leucemia/linfoma de células T do adulto e mielopatia associada ao HTLV-1/paraparesia espástica tropical além de outras doenças, enquanto o HTLV-2 pode causar alguns quadros neurológicos e alterar a evolução de HIV/Aids. Os testes sorológicos que identificam anticorpos específicos disponíveis no mercado têm falhado no diagnóstico, principalmente de infecção por HTLV-2. Vários algoritmos de testes de triagem e confirmatórios têm sido propostos, mas nenhum deles se mostrou 100% eficiente com casuística de alto risco. Muitos soros resultam em padrão indeterminado no Western blot, e os isolados virais utilizados na composição dos kits podem ser a causa desses resultados. As técnicas de biologia molecular têm sido descritas como testes confirmatórios, mas não têm sido empregadas na rotina. Desde 1991, a Seção de Imunologia do Instituto Adolfo Lutz tem estudado a infecção por HTLV-1/2, contribuindo para o diagnóstico sorológico e molecular, e tem como desafio implantar um teste laboratorial capaz de detectar infecção causada por cepas brasileiras de HTLV-2.