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Introducción. Los inmunoensayos de detección rápida de antígenos (TRA) del SARS-CoV-2, son considerados adecuados para el diagnóstico en el punto de atención. El objetivo fue conocer la concordancia entre la reacción en cadena de la polimerasa en tiempo real con transcriptasa inversa (RT-qPCR, por su sigla en inglés) y los TRA en población pediátrica. Población y métodos. Se reclutaron todos los pacientes entre 1 mes y 17 años 11 meses de edad atendidos en la Unidad Febril de Urgencia de un hospital pediátrico entre el 11 de junio y el 3 de octubre de 2021. Se utilizó el TRA Panbio COVID-19 Ag® (Abbott Diagnostic) y, comométodo de referencia, la RT-qPCR (según el protocolo de los Centros para el Control y la Prevención de Enfermedades). Resultados. Se incluyeron 6491 pacientes. La prevalencia de COVID-19 fue del 2,8 %. El92,1 % de los sujetos presentaron síntomas. La sensibilidad, la especificidad y el índice kappa de concordancia para el TRA fueron del 71,0 %, 99,9 % y 0,813, respectivamente. El índice kappa yla sensibilidad del TRA fueron significativamentemayores en el grupo de 13 a 17 años (0,89 y 82,4 %,respectivamente) cuando se los comparó con los grupos de 0 a 5 y de 6 a 12 años. Esto podría deberse a la menor carga viral observada en los pacientes menores de 12 años. Conclusión. Si bien los TRA permiten acortar el tiempo de obtención de los resultados y mejorar la estrategia de aislamiento de pacientes con COVID-19, la sensibilidad en niños menores de 12 años o asintomáticos no se encontraría dentro de los rangos recomendados, sobre todo enperíodos de baja prevalencia de la enfermedad.
Introduction. Rapid antigen tests (RAgTs) for SARS-CoV-2 are considered adequate for diagnosis at the point of care. Our objective was to establish the agreement between reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and RAgTs in the pediatric population. Population and methods. All patients aged 1 month to 17 years and 11 months seen at the Emergency Fever Unit of a children's hospital between 6-11-2021 and 10-3-2021 were recruited. The Panbio COVID-19 Ag® test (Abbott Diagnostic) was compared to the reference method RT-qPCR (as per the protocol suggested by the United States Centers for Disease Control and Prevention). Results. A total of 6491 patients were included. The prevalence of COVID-19 was 2.8%. Symptoms were observed in 92.1%. Sensitivity, specificity, and the kappa index of agreement for the RAgT were 71.0%, 99.9%, and 0.813, respectively. The kappa index and the RAgT sensitivity were significantly higher in the group aged 1317 years (0.89 and 82.4%, respectively) compared to the groups aged 05 and 612 years. This may be due to the lower viral load observed in patients younger than 12 years. Conclusion. Although RAgTs shorten the time to result and improve the isolation strategy for COVID-19 patients, their sensitivity in children younger than 12 years or asymptomatic children is not within the recommended ranges, especially during periods of low disease prevalence.
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Humans , Infant , Child, Preschool , Child , Adolescent , COVID-19/diagnosis , Sensitivity and Specificity , Emergency Service, Hospital , COVID-19 Testing , SARS-CoV-2 , Hospitals, PediatricABSTRACT
【Objective】 To develop a novel solid-phase agglutination reagent for detecting IgG irregular antibodies of red cell blood groups and evaluate its performance. 【Methods】 Monoclonal anti-RBC antibody was coated on the bottom of the microwell strips, then RBCs were bonded to the antibody and formed the monolayer by dispensing 100 μL RBC suspesion to microwell strips.RBC antigen membrane monolayer was formed by lysing RBC layer with ddH2O, then the drying medium was added to the strips and dried under reduce pressure in a vacuum dryer, thus the dried reagent microplate was obtained.Serial diluted solutions of polyclonal sheep anti-human globulin(IgG+ C3d/4)was used to react with IgG anti-D sensitized O group RBCs to select out the best indicator.Stability of membrane antigen was tested by detecting IgG anti-D and anti-E with the lowest titer by different batches of regeats. Sensitivity of the novel reagent, Capture-R Ready Screen and microcolumn gel card was carried out by detecting irregular antibodies with different titer.350 plasma samples were tested by the novel reagent and Capture-R Ready Screen to evaluate their detection ability. 【Results】 Anti-RBC solution with concentration of 20 μg/mL could fix the membrane monolayer very well on the bottom of microstrips. Sixteentimes dilution of polyclonal sheep anti-human globulin and anti-D sensitized RBCs were selected out as the best indicator.Antigen reactivity of dried RBC membrane was not weakened during the 6-monthstorage period.Sensitivity of the novel reagent was higher than Capture-R Ready Screen and microcolumn gel card. The positive consistence ratio of the novel reagent and Capture-R Ready Screen was 98.0%, the negative consistence ratio was 99.66%, and the total consistence ratio was 99.43%. 【Conclusion】 A novel solid-phase agglutination reagent with higher sensitivity and longer storage time has been developed successfully and it has an equal detection ability compared with Capture-R Ready Screen for detecting irregular alloantibodies of red cell blood groups.
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From the perspective of technical review, this paper made statistics on the supplement contents of
Subject(s)
Chemistry, Clinical/standards , China , Indicators and Reagents , Reagent Kits, Diagnostic/standardsABSTRACT
Objective:To establish the industry standard for growth hormone quantitative labelling immunoassay kit, and to validate it by chemiluminescence labeling and time-resolved fluorescence labeling method which are suitable for the standard.Methods: Different assay method kits, including magnetic particle chemiluminescent assay, electrochemiluminescence assay, chemiluminescence assay and time-resolved fluorescent assay, were used to verified the blank limitation, linearity, accuracy, precision, specificity and stability in accordance with protocol industry standard.Results: Other verification results could meet requirements of the protocol industry standard besides accuracy in part of kits couldn't achieve to anticipative remand (relative deviation couldn't be more than ±10%).Conclusion: According to the verification results, the accuracy requirements was adjusted to ±15%. The other items of industry standard were maintained. The industry standard for growth hormone quantitative labeling immunoassay kit is ultimately established. The standard would contribute to unity quality standard of growth hormone quantitative labeling immunoassay kit, and provide the basis for the supervision and administration of its production, examination, circulation, clinical application and other areas.
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Objective To establish the ELISA kit of monoclonal antibodies to Clostridium difficile toxin A.Methods A sandwich ELISA was used.Flat-bottomed 96 well polystyrene microtitre plates were coated with 100 ?l of purified rabbit monospecific antitoxin(8 ?g/ml, capturing antibody) in carbonate buffer(pH9.6) and incubated overnight at 4℃, the plates were washed once in PBS containing 0.05% Tween-20, pH7.4 (PBST). After 200 ?l of 10% BSA in PBS-T was added to the wells and incubated at 37℃ for 2h, washed 5 times in PBS-T with 3 min incubation at room temperature between each wash, 100 ?l of C. difficile toxin A or test samples in PBS-T were added to each well and incubated for 1h at 37℃, washed 5 times. Then 100 ?l of 1:1000 diluted monoclonal antibodies IgG-Horseradish peroxidase conjugate(detecting antibody) was added for 1h at 37℃, wells were washed five times with PBS-T, and 0.1ml of tetramethylbenzidines substrate was added to each well. After 15 min at 37℃ in dark, the reactions were stopped by the addition of 1 drop of 2M sulfuric acid and the A450 was measured.Results The tested specimens included culture filtrates of 2 strains of toxigenic C. difficile, 2 non-toxigenic strains of C. difficile, 26 strains of E. coli, 2 strains of S. dysenteriae, 1 strains of Bifidobacterium, 5 strains of V. cholera, 2 strain of S. typhi, 7 strains of C. botulinum, 1 strain of toxigenic C. sordllii, and 1 strain of C. butyricum. The ELISA demonstrated high specificity and good sensitivity, it detected amounts of toxin A as low as 0.1ng/ml.Conclusion An ELISA kits with high specificity and good sensitivity for the rapid detection of C. difficile toxin A was presented. It will be a beneficial tool to clinical detection of Clostridium difficile toxin A.