Inmunoanálisis quimioluminiscente de micropartículas (CMIA) en el diagnóstico de sífilis: caracterización y valorización

Introducción: La inmunoquimioluminiscencia de micropartículas (CMIA), no es recomendada en el día de hoy para el tamizaje ni confirmación de sífilis en pacientes, las guías chilenas recomiendan tamizaje con V.D.R.L y confirmación con hemaglutinación. Objetivo: Determinar la especificidad, sensibilidad y correlación diagnóstica de esta técnica respecto a la prueba treponémica de uso habitual. Materiales y Métodos: De 815 muestras obtenidas en un periodo de 6 meses, a todas las cuales se les aplicó las pruebas de VDRL, MHA-TP y CMIA, 484 muestras fueron positivas para MHA-TP. Se determinó el rendimiento, se graficaron las curvas ROC, índice de correlación y punto de corte óptimo. Resultados: La CMIA. demostró una sensibilidad de 100%, especificidad: 94,6%, VPN: 100% y VPP: 96.4% y una eficiencia de 97,8% con respecto al MHA-TP, con un índice de correlación: 0,97 y un punto de corte de 7.665, de modo que toda muestra con una CMIA. sobre este valor no necesitaría de una segunda prueba treponémica para su confirmación. El 7,11% tuvo valores intermedios de CMIA (1.0 a 7.664). Conclusión: La CMIA. es una técnica automatizada altamente sensible y específica, equiparable al MHA-TP. Aplicada como prueba inicial de testeo para sífilis incrementa la certeza diagnóstica y podría permitir el diagnóstico precoz de la enfermedad.

Background: The chemiluminescent microparticle immunoassay (CMIA) is not recommended for screening or confirmation of syphilis in patients, Chilean guidelines recommend screening with VDRL and confirmation with hemagglutination. Aim: To determine the specificity, sensitivity, and diagnostic correlation of this technique compared to the usual treponemal test. Methods: Of the 815 samples obtained over a period of 6 months, all of which were subjected to VDRL, MHATP, and CMIA. testing, 484 samples were positive for MHA-TP. The performance was determined, ROC curves were graphed, correlation index and optimal cutoff point were determined. Results: CMIA showed a sensitivity of 100%, specificity of 94.6%, NPV of 100%, PPV of 96.4%, and an efficiency of 97.8% compared to MHA-TP, with a correlation index of 0.97 and a cutoff point of 7.665, such that any sample with a CMIA. value above this value would not require a second treponemal test for confirmation. 7.11% had intermediate CMIA. values (1.0 to 7.664). Conclusion: CMIA. is a highly sensitive and specific automated technique comparable to MHA-TP. When applied as an initial screening test for syphilis, it increases diagnostic certainty and may allow for early diagnosis of the disease.

Results of a sample-to-cutoff ratio using Abbott Architect rHTLV-I/II assay allow to predict detection of HTLV-1 and HTLV-2 proviral DNA by real-time PCR / Resultados da razão sinal da amostra sobre o cutoff da reação no ensaio Abbott Architect rHTLV-I/II permite prever a detecção de DNA proviral por PCR em tempo real

The present study aims to correlate the sample-to-cutoff ratios (S/CO) distributions of reactive results for HTLV-1/2 antibodies with the detection of proviral DNA in a population of blood donor candidates. It was carried out a retrospective data search of 632 HTLV-1/2 reactive samples, submitted to confirmatory testing from January 2015 to December 2019. Serological screening was performed by chemiluminescent microparticle immunoassay Architect rHTLV-I/II, whereas confirmatory testing was performed by in-house real-time polymerase chain reaction method. 496 out of 632 samples (78%) had undetectable HTLV-1/2 proviral DNA and 136 (22%) had detectable proviral DNA. HTLV infection was not confirmed in any individual for whom the S/CO ratio value was <4, and proviral DNA detection rates gradually escalated as S/CO ratio values increased. The sensitivity and predictive positive value found for the Architect rHTLV-I/II was 100% and 22%, respectively. The receiver operating characteristic (ROC) curve analysis showed that the optimal S/CO ratio value for predicting the presence of HTLV-1/2 was 18.11. High S/CO ratios were more associated with the detection of proviral DNA. The S/CO ratio value <4 suggests excluding true HTLV infection and the risk of blood transmission (AU).

O estudo tem como objetivo correlacionar às distribuições das razões sample-to-cutoff (S/CO) de resultados reagentes para anticorpos HTLV-1/2 com a detecção de DNA proviral em uma população de candidatos à doação de sangue. Realizou-se uma busca retrospectiva de dados de 632 amostras reagentes para HTLV-1/2 submetidas à testagem confirmatória entre janeiro de 2015 a dezembro de 2019. A triagem sorológica foi realizada pelo imunoensaio quimioluminescente de micropartículas Architect rHTLV-I/II, enquanto o teste confirmatório foi realizado pelo método de PCR em tempo real in-house. 496 de 632 amostras (78%) apresentaram DNA proviral indetectável e 136 (22%) apresentaram DNA proviral detectável. A infecção por HTLV não foi confirmada em nenhum indivíduo com valor de S/CO <4 e as taxas de detecção de DNA proviral escalonaram gradualmente à medida que as razões S/CO aumentaram. A sensibilidade e valor preditivo positivo encontrados para o Architect rHTLV-I/II foram 100% e 22%, respectivamente. Utilizando análise de curva ROC, o valor de razão S/CO ideal para predizer a presença de DNA proviral foi de 18,11. Razões S/CO elevadas foram mais associadas à detecção de DNA proviral. Em suma, o valor de S/CO <4 sugere a exclusão de infecção por HTLV e o risco de transmissão pelo sangue (AU).

Detection and analysis of neutralizing antibodies against SARS-CoV-2 in convalescent plasma donors / 中国输血杂志

【Objective】 To detect the anti-SARS-CoV-2 neutralizing antibody levels in convalescent plasma (CP) and to evaluate whether it has specific anti-SARS-CoV-2 S antigen effect, so as to provide laboratory data support for clinical use of CP. 【Methods】 Nine CP donors who have recovered from COVID-19 were studied, and 4 volunteers who completed the vaccination and 3 asymptomatic infected blood donors were compared. Anti-SARS-CoV-2 antibodies including total antibody, IgM and IgG were measured by chemiluminescence microparticle immunoassays (CMIA) test in three groups. The VSV pseudovirus-based neutralization assay for evaluating neutralizing antibodies against SARS-CoV-2 was carried out in all samples. 【Results】 All samples were tested positive by the total antibody and IgG CMIA in COVID-19 CP donors and recipients of inactivated COVID-19 vaccine. High titers of IgG were observed in CP donors and vaccine recipients compared with asymptomatic blood donors. All vaccine recipients and 8 of 9 CP donors tested positive by SARS-CoV-2 pseudovirus-based neutralization test, whereas all asymptomatic blood donors tested negative. 【Conclusion】 The levels and characteristics of neutralizing antibodies among COVID-19 CP donors, vaccine recipients and asymptomatic blood donors were different. When unable to implement the pseudovirus assay to measure neutralizing antibodies, the detection of total antibody can be considered instead.

SARS-CoV-2 seroprevalence among voluntary blood donors: A retrospective analysis in Xi′an / 中国输血杂志

【Objective】 To estimate the seroprevalence of SARS-CoV-2 infection among blood donors during the COVID-19 outbreak, in order to provide reference for formulating coping strategies. 【Methods】 A total of 3 623 samples of healthy blood donors in Xi′an from January 1 to June 14, 2020 were collected and tested by chemiluminescence microparticle immunoassays(CMIA). The correlation between the number of confirmed cases of COVID-19 in Xi′an and the monthly prevalence trend of SARS-CoV-2 antibody in Xi′an was also studied. 【Results】 Among the 3 623 blood donors, 3 were reactive by CMIA, with the seroprevalence rate of SARS-CoV-2 at 0.083%(95%CI: 0.00, 0.18). The earliest yielding of SARS-CoV-2 in Xi′an was in February 4, 2020. 【Conclusion】 The SARS-CoV-2 seroprevalence rate in Xi′an is low, which is in line with the local prevalence status. It is suggested that serological detection of blood donors is a way to monitor the prevalence of COVID-19.

Comparison of RP-HPLC and CMIA Method in the Determination of Valproate in Plasma of Epileptic Pa-tients / 中国药师

Objective:To determine the valproate concentration in plasma of epilepsy patients by HPLC, and compare with the re-sults of chemiluminescence microparticle immunoassay ( CMIA) to evaluate the consistency of the two methods. Methods:HPLC and CMIA was respectively applied to determine the plasma concentration of valproate in 230 epileptic patients. The correlation of the two methods was studied by Passing-Bablok regression and Bland-Altman method. Results:The regression equation of the determination re-sults of HPLC (Y) and CMIA (X) was Y=1. 069 7X+2. 338 2 (R2 =0. 969, n=230), which showed promising correlation. Bland-Altman analysis showed that the consistency of the two methods was poor, and the values of HPLC were higher. Conclusion: HPLC and CMIA used for the determination of valproate plasma concentration show good correlation. However, the consistency is poor and there is system error. In the clinical treatment, adjustment and choice should be paid more attention.

Reality of Negative anti-HBc and Positive anti-HBe Results of Testing HBV-M with ELISA / 现代检验医学杂志

Objective To research the reality of ELISA testing results with negative anti-HBc and positive antiHBe.Methods CMIA was carried out to retest antiHBc and antiHBe of 105 samples which were initially tested to have negative antiHBc and positive antiHBe.Results Among the 105 samples retested by CMIA,there were three different results,positive antiH-Bc with positive antiHBe,negative antiHBc with negative antiHBe and positive antiHBc with negative antiHBe,whose pro-portions were 72.38%,21.91% and 5.71% respectively;the fasle negative rates of antiHBc were 78.10% in total and 93.33%,96.15% and 47.37% in 3 subgroup with S/CO 1.00~ 1.20,1.20~2.00 and 2.00~ 3.00,respectively;the true positive rates of antiHBe were 72.38% in total and 42.86%,88.14% and 56.25% in 3 subgroups with S/CO 0.00~0.10, 0.10~0.80 and 0.80 ~ 1.00,respectively.Conclusion HBV-M results with negative antiHBc and positive antiHBe by ELISA could give suggestive value and not reflect true information about antiHBc and antiHBe with three alternatives which would be obtained through retesting by a second assay.

Investigation of Pharmacokinetics and Bioequivalence of Mecobalamin in Healthy Volunteers by Chemilu-minescent Microparticle Immunoassay / 中国药师

Objective:To develop a chemiluminescent microparticle immunoassay ( CMIA) method for the determination of meco-balamin in human serum to investigate the pharmacokinetics and bioequivalence of mecobalamin. Methods:A single oral dose of two kinds of mecobalamin was given to 19 healthy volunteers in a randomized three-period crossover study. The concentrations of mecobal-amin in serum were assayed by CMIA, the main pharmacokinetic parameters were analyzed by DAS 3. 0 software, and the bioequiva-lence was evaluated. Results: The main pharmacokinetic parameters of test and reference mecobalamin tablets were as follows: tmax were (4.2 ±1.9)h and (4.4 ±2.4)h,Cmax were (322.0 ±145.4) ng·L-1 and (282.2 ±108.1) ng·L-1,t1/2 were (19.2 ±5.3) h and (20.0 ±6.3)h,AUC0-72 were (6 769.1 ±2 169.4) ng·h·L-1 and (6 400.6 ±1 921.5) ng·h·L-1. F(0-72) and F(0-∞) of the test tablets was 105. 9% ± 13. 2% and 104. 9% ± 12. 6%,respectively. Conclusion:The method is simple and precise. The two tablets are bioequivalent.