Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 69.000
Filtrar
1.
Artigo em Inglês | MEDLINE | ID: mdl-35805441

RESUMO

The SARS-CoV-2 virus, which is driving the current COVID-19 epidemic, has been detected in wastewater and is being utilized as a surveillance tool to establish an early warning system to aid in the management and prevention of future pandemics. qPCR is the method usually used to detect SARS-CoV-2 in wastewater. There has been no study using an immunoassay that is less laboratory-intensive than qPCR with a shorter turnaround time. Therefore, we aimed to evaluate the performance of an automated chemiluminescence enzyme immunoassay (CLEIA) for SARS-CoV-2 antigen in wastewater. The CLEIA assay achieved 100% sensitivity and 66.7% specificity in a field-captured wastewater sample compared to the gold standard RT-qPCR. Our early findings suggest that the SARS-CoV-2 antigen can be identified in wastewater samples using an automated CLEIA, reducing the turnaround time and improving the performance of SARS-CoV-2 wastewater monitoring during the pandemic.


Assuntos
COVID-19 , SARS-CoV-2 , COVID-19/diagnóstico , Humanos , Técnicas Imunoenzimáticas , Luminescência , RNA Viral , Águas Residuárias
2.
Int J Mol Sci ; 23(13)2022 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-35805992

RESUMO

Diagnosis of type I hypersensitivity reactions (IgE-mediated reactions) to penicillins is based on clinical history, skin tests (STs), and drug provocation tests (DPTs). Among in vitro complementary tests, the fluoro-enzyme immunoassay (FEIA) ImmunoCAP® (Thermo-Fisher, Waltham, MA, USA) is the most widely used commercial method for detecting drug-specific IgE (sIgE). In this study, we aimed to analyze the utility of ImmunoCAP® for detecting sIgE to penicillin G (PG) and amoxicillin (AX) in patients with confirmed penicillin allergy. The study includes 139 and 250 patients evaluated in Spain and Italy, respectively. All had experienced type I hypersensitivity reactions to penicillins confirmed by positive STs. Additionally, selective or cross-reactive reactions were confirmed by DPTs in a subgroup of patients for further analysis. Positive ImmunoCAP® results were 39.6% for PG and/or AX in Spanish subjects and 52.4% in Italian subjects. When only PG or AX sIgE where analyzed, the percentages were 15.1% and 30.4%, respectively, in Spanish patients; and 38.9% and 46% in Italian ones. The analysis of positive STs showed a statistically significant higher percentage of positive STs to PG determinants in Italian patients. False-positive results to PG (16%) were detected in selective AX patients with confirmed PG tolerance. Low and variable sensitivity values observed in a well-defined population with confirmed allergy diagnosis, as well as false-positive results to PG, suggest that ImmunoCAP® is a diagnostic tool with relevant limitations in the evaluation of subjects with type I hypersensitivity reactions to penicillins.


Assuntos
Hipersensibilidade a Drogas , Hipersensibilidade Imediata , Amoxicilina , Hipersensibilidade a Drogas/diagnóstico , Humanos , Hipersensibilidade Imediata/diagnóstico , Técnicas Imunoenzimáticas , Imunoglobulina E/análise , Penicilina G , Penicilinas/efeitos adversos , Testes Cutâneos
3.
Diagn Microbiol Infect Dis ; 103(4): 115723, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35717720

RESUMO

Diagnosis of parvovirus B19 (B19) infection in small-medium size clinical laboratories is most often done by nonautomated enzyme immunoassays (EIAs). Using 195 specimens we compared the analytical performance of Biotrin (Dublin, Ireland), Euroimmun (Lubeck, Germany), and Serion (Würzburg, Germany) EIAs. Sensitivity, specificity, and concordance to Biotrin assay were calculated. Overall complete agreement in the IgG and IgM results was 88.7% (173/195) and 75.9% (148/195) samples, respectively. When equivocal results were considered positive, Serion and Euroimmun highly agreed (>93.8%) with Biotrin in the IgG serology. Serion had better IgM sensitivity and specificity than Euroimmun when compared to Biotrin, although more Serion IgM equivocal results needed reflex testing. Clinical interpretation by all three assays was identical in 83% of the samples. We concluded that overall the performance of these assays was similar and both Serion and Euroimmun could be a suitable replacement for the Biotrin.


Assuntos
Parvovirus B19 Humano , Anticorpos Antivirais , Humanos , Técnicas Imunoenzimáticas , Imunoglobulina G , Imunoglobulina M , Sensibilidade e Especificidade
4.
Can J Gastroenterol Hepatol ; 2022: 5571542, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35497022

RESUMO

Background: BLEIA ™ "EIKEN" Helicobacter pylori antigen (B[EIA]) is based on the bioluminescent enzyme immunoassay (BLEIA) method that was newly developed with high sensitivity in detecting Helicobacter pylori (H. pylori) antigen in feces. Methods: In the project for H. pylori screening and treatment in Saga Prefecture in 2019, 141 students received the stool H. pylori antigen test as a secondary test. For 141 students, a comparative test was conducted between B (EIA) and extracorporeal diagnostic agents that were marketed in Japan as of 2019. The detection performance of H. pylori ATCC43504 standard strain and H. pylori antigen in commercial human fecal specimens were conducted. Results: The comparison of B (EIA) with Quick Chaser TM H. pylori (Q [IC]) revealed positive and negative concordance ratios of B (EIA) to Q (IC) of 100.0% (110/110) and 71.0% (22/31), respectively. A comparative test was conducted between B (EIA) and extracorporeal diagnostic agents that were marketed in Japan as of 2019, and B (EIA) was most sensitive on "detecting H. pylori antigen of ATCC43504 standard strain" and "detecting H. pylori antigen in commercial human fecal specimens," compared with other kits. Nine dissociated specimens that were negative for Q (IC) and positive for B (EIA) were confirmed. The measured value of B (EIA) in the dissociation samples were 1.3-87.4 cutoff index in the range that can be evaluated as negative by other fecal H. pylori antigen test kits, all the dissociation samples were H. pylori antigen-positive cases, and finally the cause of result divergence was presumed as false negative due to insufficient sensitivity of Q (IC). Conclusion: B (EIA) that is based on the BLEIA method, which applies firefly luciferase luminescence, is more sensitive than stool antigen test kits that are currently marketed in Japan and is very useful in diagnosing H. pylori infection, especially in situations where noninvasive tests are preferred, such as in children.


Assuntos
Helicobacter pylori , Criança , Fezes , Humanos , Técnicas Imunoenzimáticas , Japão
5.
Food Chem ; 392: 133232, 2022 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-35636182

RESUMO

Highly sensitive and accurate detection of chloramphenicol is of paramount importance for food safety. Herein, an enzyme-modulated photothermal immunosensor that uses a self-calibrated thermal imaging system (SCTIS) as signal read-out was developed for detecting chloramphenicol. In this immunosensor, alkaline phosphatase was used as a modulator of the photothermal conversion. It could hydrolyze the substrate into ascorbic acid, thereby reducing oxidized 3,3',5,5'-tetramethylbenzidine, which exhibited a near-infrared laser-driven photothermal effect. For precise temperature measurement, the SCTIS was designed by using the temperature compensation of a ceramic chip to enable real-time self-calibration of the temperature. This SCTIS-based immunosensor could detect chloramphenicol with a LOD of 9 pg/mL in 2 h, and relative standard derivations from 3.95% to 13.58%. The average recoveries in milk and egg samples ranged from 76% to 114%. This versatile sensing strategy can detect various targets by altering recognition elements, thus has wide applicability in food safety testing and monitoring.


Assuntos
Técnicas Biossensoriais , Cloranfenicol , Animais , Técnicas Biossensoriais/métodos , Cloranfenicol/análise , Imunoensaio/métodos , Técnicas Imunoenzimáticas , Leite/química
6.
Microbiol Spectr ; 10(3): e0103221, 2022 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-35499325

RESUMO

This study includes 259 consecutive nasopharyngeal swabs which tested positive for a molecular SARS-CoV-2 test and 77 subjects who were followed longitudinally, with nasopharyngeal swabs performed weekly until clinical recovery and a negative result for the molecular test were reached. All swabs were also tested with a Lumipulse SARS-CoV-2 chemiluminescence enzyme immunoassay (CLEIA) antigen assay. The antigen test was positive in 169 (65.3%) out of the 259 subjects, while no antigen was detected in 90 subjects (34.7%). In the antigen-positive subjects, clinical status moved slightly toward a more frequent presence of symptoms. Longitudinal follow-up shows how the time of negativization has a faster kinetic in the antigenic test than in the molecular test. Antigenic test result values, considered as a time-dependent covariate and log-transformed, were highly associated with the time to negative swab, with good prediction ability. Receiver operating characteristic (ROC) curve analysis showed a very good discrimination ability of antigenic tests in classifying negative swabs. The optimal cutoff which jointly maximized sensitivity and specificity was 1.55, resulting in an overall accuracy of 0.75, a sensitivity of 0.73, and a specificity of 0.83. After dichotomizing the antigenic test according to the previously determined cutoff value of 1.55, the time-dependent covariate Cox model again suggests a highly significant association of antigenic test values with the time to negative swab molecular: a subject with an antigenic test value lower than 1.55 had almost a 13-fold higher probability to also result negative in the molecular test compared to a subject with an antigenic test value higher than 1.55. IMPORTANCE Our work explores the possibility of using a sensible and reliable antigenic test in a wider range of SARS-CoV-2 diagnostic and clinical applications. Furthermore, this tool seems particularly promising in follow-up with infected subjects, because while the molecular test frequently yields the persistence of low positivities, raising yet unanswered questions, this antigenic test shows more uniform and faster negativization during the evolution of the infection, somehow paralleling the dynamics of infectivity. Although more data will be required to definitely prove it, we believe these findings might be of great interest.


Assuntos
COVID-19 , SARS-CoV-2 , COVID-19/diagnóstico , Seguimentos , Humanos , Técnicas Imunoenzimáticas , Luminescência , SARS-CoV-2/genética
7.
Front Endocrinol (Lausanne) ; 13: 859347, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35388294

RESUMO

Since April 2021, the plasma aldosterone concentration has been measured by chemiluminescent enzyme immunoassay (CLEIA) in Japan. In the present study, we developed a new CLEIA using a two-step sandwich method to measure the 24-hour urine aldosterone level. We collected 115 urine samples and measured 24-hour urine aldosterone levels employing radioimmunoassay (RIA), CLEIA, and liquid chromatography-tandem mass spectrometry (LC-MS/MS). The results showed that the 24-hour urine aldosterone levels measured using CLEIA and LC-MS/MS were significantly correlated (ρ = 0.992, P < 0.0001). Based on the results of Passing-Bablok regression analysis, the slope was 0.992 and the intercept -19.3. The 24-hour urine aldosterone levels measured using CLEIA and RIA were also significantly correlated (ρ = 0.905, P < 0.0001). However, the aldosterone level measured by CLEIA was lower than that measured by RIA (slope, 0.729; intercept, 120.9). In Japan, a new guideline for primary aldosteronism has been announced, with changes in the aldosterone measurement method. The cutoff values for oral sodium loading test (OSLT) were changed, but clinical verification using real-world urine samples has not been performed. Therefore, we examined the cut-off value of the 24-hour urine aldosterone level after the OSLT. Receiver operating characteristic analysis revealed a cut-off value for primary aldosteronism of 3 µg/day.


Assuntos
Aldosterona , Hiperaldosteronismo , Cromatografia Líquida , Humanos , Técnicas Imunoenzimáticas , Cloreto de Sódio , Espectrometria de Massas em Tandem/métodos
8.
Int Arch Allergy Immunol ; 183(8): 814-823, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35378542

RESUMO

BACKGROUND: Previous studies demonstrated that birch pollen-related foods can cause late eczematous responses in birch pollen-sensitized patients with atopic dermatitis (AD). However, suitable markers to predict birch pollen-related food allergy in patients with AD are still lacking. OBJECTIVE: We evaluated the correlation of the results from ImmunoCAP® fluorescence enzyme immunoassay (FEIA) singleplex and ImmunoCAP® immuno solid-phase allergen chip (ISAC) multiplex system in AD patients and investigated the diagnostic validity of allergen microarray analysis, measuring specific IgE (sIgE) with ImmunoCAP® ISAC to predict birch pollen-related food allergy in patients with AD. METHODS: A total of 19 children and adults with AD, existing IgE-mediated birch pollen sensitization, and suspected birch pollen-related food allergy underwent a double-blind placebo-controlled food challenge (DBPCFC) in the clinical routine. Total and sIgE levels to birch pollen, Bet v 1, Bet v 2, and birch pollen-related foods (apple, carrot, celery, and hazelnut) were determined prior to the DBPCFC by ImmunoCAP®-FEIA. Additionally, allergen microarray ImmunoCAP® ISAC analysis was performed. Data were analyzed retrospectively. RESULTS: Twelve out of 19 patients (63% responders) experienced an allergic reaction upon DBPCFC. Overall, 7 patients (37%) developed a significant deterioration of AD with a median increase of 12.4 points in the scoring of atopic dermatitis (SCORAD) index (range 10.0-15.7). Oral allergy syndrome was the predominant immediate-type symptom (n = 11/12 responders). There were no differences in sensitization frequencies regarding allergens of the pathogenesis-related protein family 10 between responders and non-responders. In all patients, correlation of IgE levels determined with ImmunoCAP® ISAC and ImmunoCAP®-FEIA, respectively, was significant with high correlation coefficients regarding birch pollen allergen extract, rBet v 1, and rBet v 2 (rs > 0.8, p < 0.001) and lower but also significant correlation coefficients regarding food allergens (rs < 0.8, p < 0.05-<0.001). CONCLUSION: ImmunoCAP® ISAC microarray allows displaying a differentiated sensitization profile in birch pollen-sensitized patients with AD. However, IgE-mediated sensitization against birch pollen-related allergens revealed by the allergen multiplex system does not predict late eczematous reactions upon DBPCFC with birch pollen-related foods.


Assuntos
Dermatite Atópica , Hipersensibilidade Alimentar , Adulto , Alérgenos , Betula , Criança , Dermatite Atópica/diagnóstico , Hipersensibilidade Alimentar/diagnóstico , Humanos , Técnicas Imunoenzimáticas , Imunoglobulina E , Análise em Microsséries , Pólen , Estudos Retrospectivos
9.
Sex Transm Dis ; 49(6): 453-457, 2022 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-35312664

RESUMO

BACKGROUND: Automated chemiluminescent microparticle immunoassays (CMIAs) are the most common first step at high-volume laboratories for syphilis screening. If the initial screening test is reactive, 1 more treponemal test is required, resulting in increased cost. In this multicenter study, we aimed to determine the correlation between the CMIA signal-to-cutoff ratio (S/Co) and the confirmatory tests to reduce unnecessary confirmatory testing. METHODS: Eight hospitals from 5 provinces participated in this study. All laboratories used Architect Syphilis TP CMIA (Abbott Diagnostics, Abbott Park, IL) for initial screening. Treponema pallidum hemagglutination (TPHA), rapid plasma reagin (RPR), and fluorescent treponemal antibody absorption (FTA-ABS) were used as confirmatory tests according to the reverse or European Centre for Disease Prevention and Control algorithms. A receiver operating characteristic analysis was used to determine the optimal S/Co ratio to predict the confirmation results. RESULTS: We evaluated 129,346 serum samples screened by CMIA between January 2018 and December 2020. A total of 2468 samples were reactive; 2247 (91%) of them were confirmed to be positive and 221 (9%) were negative. Of the 2468 reactive specimens, 1747 (70.8%) had an S/Co ratio ≥10.4. When the S/Co ratios were ≥7.2 and ≥10.4, the specificity values were determined to be 95% and 100%, respectively. In a subgroup of 75 CMIA-positive patients, FTA-ABS was performed and 62 were positive. Among these FTA-ABS-positive patients, 24 had an S/Co ratio <10.4, and negative TPHA and RPR. CONCLUSIONS: We propose a potentially cost-effective reverse screening algorithm with a treponemal CMIA S/Co ratio ≥10.4, obviating the need for secondary treponemal testing in about 71% of the screening-reactive samples. This would substantially reduce the confirmatory testing volume and laboratory expenses. However, in high-risk group patients with CMIA positive results, S/Co ratio <10.4, and negative TPHA and RPR, FTA-ABS may be used for confirmation.


Assuntos
Sífilis , Anticorpos Antibacterianos , Testes de Hemaglutinação , Humanos , Imunoensaio , Técnicas Imunoenzimáticas , Sorodiagnóstico da Sífilis/métodos , Treponema pallidum
10.
J Infect Chemother ; 28(6): 757-761, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35249819

RESUMO

INTRODUCTION: A rapid membrane enzyme immunoassays (EIA) are frequently used to diagnose Clostridioides difficile infection (CDI). If EIA does not provide a definitive CDI diagnosis, whether treatment with anti-CD agents is to be performed depends on the pathogenesis and severity of the disease. In Japan, "MN criteria" have been proposed for the classification of disease severity. In this study, we investigated the association between disease severity and CDI prognosis when MN criteria are used. METHODS: This study included 102 patients diagnosed with CDI between April 2015 and March 2020. The disease serverity classification accorditng to MN criteria was divided into two groups: non-severely ill (mild to moderate) and severely ill (severe to critical) group. RESULTS: Mortality was significantly higher in severely ill patients than non-severely ill patients (46.7% vs. 13.8%, p = 0.0025). Multivariable analysis showed that the mortality of patients with CDI was significantly associated with advanced age (odds ratio [OR] = 1.1; 95% confidence interval [CI] = 1.0-1.2; p = 0.019) and disease severity (OR = 4.2; 95% CI = 1.2-14.8; p = 0.023). DISCUSSION: The classification of disease severity according to the MN criteria would be particularly useful in predicting the patients' prognoses.


Assuntos
Clostridioides difficile , Infecções por Clostridium , Infecções por Clostridium/diagnóstico , Infecções por Clostridium/tratamento farmacológico , Humanos , Técnicas Imunoenzimáticas , Prognóstico , Índice de Gravidade de Doença
11.
Methods Mol Biol ; 2446: 547-554, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35157293

RESUMO

Compared with traditional polyclonal and monoclonal antibodies, nanobodies derived from camelid heavy-chain antibodies have several advantages including small size, unique structure and binding geometry, high stability, and robust expression yields in numerous systems. Nanobody-based assays can also exhibit superior performance for immunodetection. Here, we describe protocols for three nanobody-based immunoassays for the detection of small chemical contaminants in environmental or agricultural samples: enzyme-linked immunosorbent assay (ELISA), fluorescence enzyme immunoassay (FEIA), and bioluminescent enzyme immunoassay (BLEIA). These methods are based on hapten-specific nanobodies, nanobody-alkaline phosphatase fusion proteins, and nanobody-nanoluciferase fusion proteins, respectively.


Assuntos
Anticorpos de Domínio Único , Ensaio de Imunoadsorção Enzimática/métodos , Haptenos , Imunoensaio/métodos , Técnicas Imunoenzimáticas , Anticorpos de Domínio Único/química
12.
PLoS Negl Trop Dis ; 16(2): e0010241, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-35196321

RESUMO

The laborious microscopic agglutination test (MAT) is the gold standard serologic test for laboratory diagnosis of leptospirosis. We developed EIA based serologic assays using recombinant proteins (rLigA, rLigB, rLipL32) and whole-cell extracts from eight Leptospira serovars as antigen and assessed the diagnostic performance of the new assay within each class, against MAT positive (MAT+) human sera panels from Portugal/PT (n = 143) and Angola/AO (n = 100). We found that a combination of recombinant proteins rLigA, rLigB and rLipL32 correctly identified antigen-specific IgG from patients with clinical and laboratory confirmed leptospirosis (MAT+) with 92% sensitivity and ~ 97% specificity (AUC 0.974) in serum from the provinces of Luanda (LDA) and Huambo (HBO) in Angola. A combination of whole cell extracts of L. interrogans sv Copenhageni (LiC), L. kirschneri Mozdok (LkM), L. borgpetersenii Arborea (LbA) and L. biflexa Patoc (LbP) accurately identified patients with clinical and laboratory confirmed leptospirosis (MAT+) with 100% sensitivity and ~ 98% specificity for all provinces of Angola and Portugal (AUC: 0.997 for AO/LDA/HBO, 1.000 for AO/HLA, 0.999 for PT/AZ and 1.000 for PT/LIS). Interestingly, we found that MAT+ IgG+ serum from Angola had a significantly higher presence of IgD and that IgG3/IgG1 isotypes were significantly increased in the MAT+ IgG+ serum from Portugal. Given that IgM/IgD class and IgG3/IgG1 specific isotypes are produced in the earliest course of infection, immunoglobulin G isotyping may be used to inform diagnosis of acute leptospirosis. The speed, ease of use and accuracy of EIA tests make them excellent alternatives to the laborious and expensive MAT for screening acute infection in areas where circulating serovars of pathogenic Leptospira are well defined.


Assuntos
Leptospira , Leptospirose , Doença Aguda , Testes de Aglutinação , Anticorpos Antibacterianos , Antígenos de Bactérias , Extratos Celulares , Ensaio de Imunoadsorção Enzimática , Humanos , Técnicas Imunoenzimáticas , Imunoglobulina D , Imunoglobulina G , Proteínas Recombinantes , Testes Sorológicos
13.
Zhonghua Liu Xing Bing Xue Za Zhi ; 43(1): 72-77, 2022 Jan 10.
Artigo em Chinês | MEDLINE | ID: mdl-35130655

RESUMO

Objective: To estimate the incidence of HIV-1 infection in men who have sex with men (MSM) in key areas of China through HIV-1 limiting antigen avidity enzyme immunoassay (LAg-Avidity EIA), analyze the deviation from the actual results and identify influencing factors, and provided reference for improving the accuracy of estimation results. Methods: Based on the principle of the cohort randomized study design, 20 cities were selected in China based on population size and the number of HIV-positive MSM. The sample size was estimated to be 700 according to the HIV-1 infection rate in MSM. MSM mobile phone app. was used to establish a detection appointment and questionnaire system, and the baseline cross-sectional survey was conducted from April to November 2019. LAg-Avidity EIA was used to identify the recent infected samples. The incidence of HIV-1 infection was calculated and then adjusted based on the estimation formula designed by WHO. The influencing factors were identified by analyzing the sample collection and detection processes. Results: Among the 10 650 blood samples from the participants, 799 were HIV-positive in initial screening, in which 198 samples (24.78%) missed during confirmation test. Only 621 samples were received by the laboratory. After excluding misreported samples, 520 samples were qualified for testing. A total of 155 samples were eventually determined as recent infection through LAg-Avidity EIA; Based on the estimation formula , the incidence of HIV-1 infection in MSM in 20 cities was 4.06% (95%CI:3.27%-4.85%), it increased to 5.53% (95%CI: 4.45%-6.60%)after the adjusting for sample missing rate. When the sample missing rate and misreporting rate were both adjusted, the incidence of HIV-1 infection in the MSM increased to 5.66% (95%CI:4.67%-6.65%). The actual incidence of HIV-1 infection in MSM in the 20 cities might be between 4.06% and 5.66%. Conclusions: Sample missing and misreporting might cause the deviation of the estimation of HIV-1 infection incidence. It is important to ensure the sample source and the quality of sample collection and detection to reduce the deviation in the estimation of HIV-1 infection incidence.


Assuntos
Infecções por HIV , HIV-1 , Minorias Sexuais e de Gênero , Estudos Transversais , Infecções por HIV/diagnóstico , Infecções por HIV/epidemiologia , Homossexualidade Masculina , Humanos , Técnicas Imunoenzimáticas , Incidência , Masculino
14.
J Appl Lab Med ; 7(1): 75-80, 2022 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-34996078

RESUMO

BACKGROUND: Antineutrophil cytoplasmic antibody (ANCA) testing by the indirect immunofluorescence assay (IFA) is important for the diagnosis of autoimmune vasculitis. A common analytical interference for ANCA-IFA is the presence of an antinuclear antibody (ANA), which can cause an apparent perinuclear ANCA (pANCA) result on ethanol-fixed neutrophils. Here, the association of ANA patterns, titers, and concentrations with pANCA interference is investigated. METHODS: Samples positive for ANA by IFA with homogeneous, speckled, dense fine speckled (DFS), and centromere patterns were tested for ANA by enzyme immunoassay (EIA)] and for ANCA by IFA on ethanol-fixed neutrophils. Titers and concentrations were determined for the ANA-IFA and EIA, respectively, and correlated with the frequency of pANCA interpretations. RESULTS: For ANA-EIA positive samples (≥1.1U), 20.0% led to a pANCA interpretation compared to 5.1% for negative samples (≤1.0U). For samples positive by ANA-IFA, 12.9% resulted in a pANCA interpretation. Interference on pANCA correlated with ANA-IFA titer, with ANA titers ≥1:1280 identified as pANCA positive in 20.9% of samples compared to 9.7% for titers <1:1280. There was also a correlation with ANA pattern, as homogeneous samples were most likely to be called positive for pANCA (31.7%), followed by speckled (8.8%), DFS (6.8%), and centromere (3.6%). CONCLUSIONS: Positivity for ANA by EIA is associated with increased prevalence of pANCA interpretation. Samples positive for ANA by IFA also demonstrated this association, particularly with higher-titer, homogeneous patterns. Laboratories can use this information to determine an optimal workflow for when investigating potential pANCA interferences.


Assuntos
Anticorpos Antinucleares , Neutrófilos , Técnica Indireta de Fluorescência para Anticorpo , Humanos , Técnicas Imunoenzimáticas
15.
Microbiol Spectr ; 10(1): e0078621, 2022 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-34985331

RESUMO

Seroepidemiological studies to monitor antibody kinetics are important for assessing the extent and spread of SARS-CoV-2 in a population. Noninvasive sampling methods are advantageous for reducing the need for venipuncture, which may be a barrier to investigations, particularly in pediatric populations. Oral fluids are obtained by gingiva-crevicular sampling from children and adults and are very well accepted. Enzyme immunoassays (EIAs) based on these samples have acceptable sensitivity and specificity compared to conventional serum-based antibody EIAs and are suitable for population-based surveillance. We describe the development and evaluation of SARS-CoV-2 IgG EIAs using SARS-CoV-2 viral nucleoprotein (NP) and spike (S) proteins in IgG isotype capture format and an indirect receptor-binding-domain (RBD) IgG EIA, intended for use in children as a primary endpoint. All three assays were assessed using a panel of 1,999 paired serum and oral fluids from children and adults participating in school SARS-CoV-2 surveillance studies during and after the first and second pandemic wave in the United Kingdom. The anti-NP IgG capture assay was the best candidate, with an overall sensitivity of 75% (95% confidence interval [CI]: 71 to 79%) and specificity of 99% (95% CI: 78 to 99%) compared with paired serum antibodies. Sensitivity observed in children (80%, 95% CI: 71 to 88%) was higher than that in adults (67%, CI: 60% to 74%). Oral fluid assays (OF) using spike protein and RBD antigens were also 99% specific and achieved reasonable but lower sensitivity in the target population (78%, 95% CI [68% to 86%] and 53%, 95% CI [43% to 64%], respectively). IMPORTANCE We report on the first large-scale assessment of the suitability of oral fluids for detection of SARS-CoV-2 antibody obtained from healthy children attending school. The sample type (gingiva-crevicular fluid, which is a transudate of blood but is not saliva) can be self collected. Although detection of antibodies in oral fluids is less sensitive than that in blood, our study suggests an optimal format for operational use. The laboratory methods we have developed can reliably measure antibodies in children, who are able to take their own samples. Our findings are of immediate practical relevance for use in large-scale seroprevalence studies designed to measure exposure to infection, as they typically require venipuncture. Overall, our data indicate that OF assays based on the detection of SARS-CoV-2 antibodies are a tool suitable for population-based seroepidemiology studies in children and highly acceptable in children and adults, as venipuncture is no longer necessary.


Assuntos
Anticorpos Antivirais/análise , COVID-19/diagnóstico , Líquido do Sulco Gengival/imunologia , Imunoglobulina G/análise , SARS-CoV-2/imunologia , Adolescente , Criança , Pré-Escolar , Humanos , Técnicas Imunoenzimáticas , Lactente , Sensibilidade e Especificidade , Estudos Soroepidemiológicos
16.
Artigo em Inglês | IBECS | ID: ibc-203287

RESUMO

BackgroundSerological diagnosis of infections due to measles and rubella viruses is done by IgM detection. The aim of this study was to comparatively evaluate commercial systems for detecting IgM against both viruses, including those of ELISA, in indirect and capture formats, chemiluminescence and electrochemiluminescence.MethodsSeven (for rubella) and six (for measles) assays were studied. One hundred and sixty two samples were included in the study (from 90 rubella and 72 measles cases), and all were analyzed in all the assays.ResultsThe ranges of sensitivity, specificity and agreement for rubella were 94.8–100%, 52.4–100% and 75.5–98.1%, respectively. The corresponding ranges for measles assays were 87.0–100%, 53.3–100%, and 73.0–99.4%.ConclusionThe best-performing assays were chemiluminescence (for measles and rubella IgM), and electrochemiluminescence (for rubella IgM).


El diagnóstico serológico de las infecciones por los virus de la rubéola y del sarampión se realiza por detección de IgM específica. El objetivo de este estudio fue evaluar comparativamente sistemas comerciales para la detección de IgM frente a ambos virus, incluyendo ensayos de ELISA, tanto con metodologías indirectas como de captura, así como quimioluminiscencia y electroquimioluminiscencia.MétodosSe estudiaron 7 ensayos para rubéola y 6 para sarampión. Se emplearon 162 muestras (de 90 casos de rubéola y de 72 de sarampión) que se analizaron en todos los ensayos.ResultadosLos rangos de sensibilidad, especificidad y concordancia para los ensayos de rubéola fueron 94,8-100%, 52,4-100% y 75,5-98,1%, respectivamente. Los rangos correspondientes para los ensayos de sarampión fueron 87-100%, 53,3-100% y 73-99,4%, respectivamente.ConclusiónLos mejores ensayos fueron quimioluminiscencia (para IgM frente a rubéola y a sarampión) y electroquimioluminiscencia (para IgM frente a rubéola).


Assuntos
Humanos , Ciências da Saúde , Benchmarking , Imunoglobulina M , Vírus da Rubéola , Sarampo , Técnicas Imunoenzimáticas , Imunoensaio de Fluorescência por Polarização , Microbiologia , Testes Sorológicos
17.
J Clin Virol ; 146: 105048, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34863056

RESUMO

Direct detection of SARS-CoV-2 viral antigens could replace RT-PCR, provided that its clinical performance is validated in different epidemiological settings. Here, we evaluated the performance of the VITROS Antigen test, an enzyme immunoassay detecting a SARS-CoV-2 antigen, in NPSs from 3 cohorts of patients. METHODS: Three cohorts including SARS-CoV-2 RNA-positive samples collected during the first and second wave of the French epidemic between March 2020 and February 2021 (including variant B.1.1.7/α and variant B.1.351/ß). RESULTS: Among the 1763 prospectively tested subjects, 8.2% (145/1763) were SARS-CoV-2 RNA-positive by RT-PCR. Using Ct ≤ 30 and Ct ≤ 35 as thresholds, the sensitivities of the antigen assay were 98.8% (93.6-100%) and 93.5% (87.0-97.3%), respectively. The overall specificity of the assay was 100% (1614/1614; 99.8-100%). In a retrospective cohort of subjects infected with variants of concern, 90.4% (47/52) of NPSs containing B. B.1.1.7/α (Ct ≤ 35) and 100% (7/7) of those containing B.1.351/ß were positive with the VITROS EIA SARS-CoV-2 Antigen test. CONCLUSION: The excellent performance of the EIA Antigen test reported here, including in patients infected with viral "variants of concern", support the use of high-throughput, EIA-based SARS-CoV-2 antigen assays as an alternative or complement to nucleic acid testing in order to scale-up laboratory screening and diagnostic capacities.


Assuntos
COVID-19 , SARS-CoV-2 , Antígenos Virais , Humanos , Imunoensaio , Técnicas Imunoenzimáticas , RNA Viral , Estudos Retrospectivos , Sensibilidade e Especificidade
18.
Mycopathologia ; 187(1): 129-131, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34802111

RESUMO

A sandwich enzyme immunoassay (EIA) for the detection of Histoplasma antigens (Ag) in urine, developed by Optimum Imaging Diagnostics (OIDx) was evaluated. A verification using a standardized reference panel of urine samples found sensitivity of 92%, specificity of 32% and accuracy of 51%. In this study, the OIDx Histoplasma urinary Ag EIA displayed high sensitivity, however, in non-histoplasmosis cases this EIA displayed false-positive results in 68% of specimens tested.


Assuntos
Histoplasma , Histoplasmose , Antígenos de Fungos , Histoplasmose/diagnóstico , Humanos , Técnicas Imunoenzimáticas , Sensibilidade e Especificidade
19.
Dig Dis Sci ; 67(1): 16-25, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34846676

RESUMO

Infectious diarrhea is caused by a variety of pathogens, including viruses, bacteria, and parasitic organisms. Though the causative agent of diarrhea has historically been evaluated via stool cultures, recently, culture-independent diagnostic tests (CIDT) have been developed and utilized with increasing frequency. Current practice guidelines recommend their use as adjuncts to stool cultures for diagnosing acute and chronic diarrhea. The three principal CIDT are microscopy, enzyme-based immunoassays (EIAs), and molecular based polymerase chain reaction (PCR). This review explores the common causes of infectious diarrhea, the basics of stool culture, the diagnostic utility of these three culture-independent modalities, and the strengths and weaknesses of all currently available clinical techniques. It also outlines considerations for specific populations including returning travelers and those with inflammatory bowel disease.


Assuntos
Diarreia , Fezes/microbiologia , Técnicas Imunoenzimáticas/métodos , Técnicas Microbiológicas , Microscopia/métodos , Reação em Cadeia da Polimerase/métodos , Meios de Cultura , Diarreia/diagnóstico , Diarreia/microbiologia , Humanos , Técnicas Microbiológicas/métodos
20.
J Infect Chemother ; 28(2): 273-278, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34857462

RESUMO

BACKGROUND: Levels of 50% neutralizing titer (NT50) reflect the a vaccine-induced humoral immunity after the vaccination against the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Measurements of NT50 are difficult to implement in large quantities. A high-throughput laboratory test is expected for determining the level of herd immunity against SARS-CoV-2. METHODS: We analyzed samples from 168 Japanese healthcare workers who had completed two doses of the BNT162b2 vaccine. We analyzed immunoglobulin G (IgG) index values against spike protein (SP) using automated chemiluminescent enzyme immunoassay system AIA-CL and analyzed the background factors affecting antibody titer. SP IgG index was compared with 50% neutralization titers. RESULTS: The median SP IgG index values of the subjects (mean age = 43 years; 75% female) were 0.1, 1.35, 60.80, and 97.35 before and at 2, 4, and 6 weeks after the first dose, respectively. At 4 and 6 weeks after the first dose, SP IgG titers were found to have positive correlation with NT50 titer (r = 0.7535 in 4 weeks; r = 0.4376 in 6 weeks). Proportions of the SP IgG index values against the Alpha, Beta, Gamma, and Delta variants compared with the original strain were 2.029, 0.544, 1.017, and 0.6096 respectively. Older age was associated with lower SP IgG titer index 6 weeks after the first dose. CONCLUSIONS: SP IgG index values were rised at 3 weeks after two doses of BNT162b2 vaccination and have positive correlation with NT50. SP IgG index values were lower in the older individuals and against Beta and Delta strain.


Assuntos
COVID-19 , Adulto , Idoso , Anticorpos Neutralizantes , Anticorpos Antivirais , Vacinas contra COVID-19 , Feminino , Humanos , Técnicas Imunoenzimáticas , Masculino , SARS-CoV-2 , Vacinação
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...