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Ryan F. Relich - One of the best experts on this subject based on the ideXlab platform.
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Viral Antigen Detection
Clinical Virology Manual, 2016Co-Authors: Diane S. Leland, Ryan F. RelichAbstract:Laboratorians continually seek methodologies that yield accurate results in a timely fashion, are cost effective, and require less technical expertise. Diagnosis of viral infections via viral Antigen Detection methods such as immunofluorescence (FA), immunochromatography (lateral flow) (IC), and enzyme immunoassays (EIA) offer many of these attractive features and are useful for direct Detection of viral Antigens in an array of clinical specimens and for identification of cultivated viruses. Whether the Detection method is FA, rapid IC, or EIA, Detection of Antigens of the common respiratory viruses (i.e., adenovirus; influenza virus [Flu] A and B; parainfluenza virus [PIV] −1, −2, and −3 and respiratory syncytial virus [RSV]), has been shown to be more useful in patient management than either traditional virus isolation (1, 2, 3) or viral Detection in rapid culture using centrifugation-enhanced inoculation (4). There is considerable variability in the sensitivity, specificity, technical considerations, and turnaround time among the various methods, and each method may perform differently depending on the viral target. This chapter deals with principles of FA, IC, and EIA and their contemporary applications in viral Antigen Detection.
Gerard H. Koëter - One of the best experts on this subject based on the ideXlab platform.
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Antigen Detection in oropharyngeal secretions for rapid diagnosis of pneumococcal pneumonia
European journal of clinical microbiology & infectious diseases : official publication of the European Society of Clinical Microbiology, 1993Co-Authors: Wim Boersma, A. Löwenberg, J. A. M. Snijder, Yvette Holloway, H. Kuttschrütter, Gerard H. KoëterAbstract:To determine the value of Detection of Antigen in the oropharynx in the diagnosis of pneumococcal pneumonia, oropharyngeal secretions were cultured for the presence ofStreptococcus pneumoniae and tested for the presence of pneumococcal Antigen. Sputum (if available) collected on the same day was also investigated for the presence of Antigen. Detection of pneumococcal Antigen was found to be directly related to the severity of pneumococcal carriership or infection (p
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The Role of Antigen Detection in Pneumococcal Carriers: A Comparison between Cultures and Capsular Antigen Detection in Upper Respiratory Tract Secretions
Scandinavian journal of infectious diseases, 1993Co-Authors: Wim Boersma, A. Löwenberg, H. Kuttschrütter, Y. Holloway, Jan A. M. Snijder, Gerard H. KoëterAbstract:During the winter season upper respiratory tract secretions from 166 patients with stable chronic obstructive pulmonary disease (COPD) or asthma were simultaneously cultured for Streptococcus pneumoniae and tested for pneumococcal capsular Antigen. Latex agglutination was employed to investigate the effect of pneumococcal carriership on pneumococcal capsular Antigen Detection in upper respiratory tract secretions. All specimens originating from the oropharynx, nasopharynx and saliva were both cultured and investigated in parallel for the presence of Antigen. The recovery of pneumococci from the different areas was unequally distributed (oropharynx 29%, nasopharynx 8%, and saliva 16%), with the highest isolation rate from the oropharynx alone. Only 4 (3%) of the oropharyngeal swabs, 1 (1%) of the nasopharyngeal swabs and 14 (9%) of the saliva specimens yielded both pneumococcal Antigen and a positive culture for S. pneumoniae. A further 9 (6%) of the oropharyngeal swabs, 5 (3%) of the nasopharyngeal swabs, and 50 (33%) of the saliva specimens were Antigen positive only, with no pneumococci isolated on culture. It is speculated that these reactions were due to cross-reacting microorganisms (especially alpha-haemolytic streptococci) present in saliva and contaminating the oropharynx and the nasopharynx. Quantitative cultures of 9 oropharyngeal swabs yielded S. pneumoniae in concentrations too low to be detectable by latex agglutination. The study indicates that there is a poor relation between pneumococcal colonization and Antigen Detection in the oropharynx and nasopharynx. Antigen present in these secretions is probably not an important disrupting factor by contamination when detecting pneumococcal Antigen in washed sputum. The false positive Antigen results in saliva are probably due to cross-reactions with alpha-haemolytic streptococci.
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Pneumococcal capsular Antigen Detection and pneumococcal serology in patients with community acquired pneumonia.
Thorax, 1991Co-Authors: Wim Boersma, A. Löwenberg, J. A. M. Snijder, Yvette Holloway, H. Kuttschrütter, Gerard H. KoëterAbstract:BACKGROUND: Methods to determine the microbial cause of community acquired pneumonia include Detection of pneumococcal Antigen and measurement of pneumococcal capsular antibody response. Their usefulness compared with conventional microbiological techniques was investigated in patients with pneumonia, some of whom had been treated with antibiotics. METHODS: Pneumococcal capsular Antigen was detected by latex agglutination in sputum and the results compared prospectively with results of conventional microbiological techniques in 90 patients with community acquired pneumonia. Serum, urine, and pleural fluid samples were also tested for Antigen. Serum pneumococcal capsular antibody titres were measured. RESULTS: A diagnosis was established by conventional microbiological techniques in 53 patients, 30 of whom had pneumococcal pneumonia. The sensitivity of Antigen Detection in first day sputum specimens (n = 18) in those with pneumococcal pneumonia was 94%; Antigen was present in 23 of the 27 patients who produced representative sputum on admission and during follow up. The specificity of Antigen Detection in sputum in patients with non-pneumococcal pneumonia and lung infarction was 87%. Antigen was present in 12 of 25 patients with pneumonia of unknown aetiology who produced representative sputum. Antigen was rarely detected in serum and urine, but was present in pleural fluid in three of four patients with pneumococcal pneumonia and in all four patients with pneumonia of unknown aetiology. Pneumococcal Antigen remained detectable in patients treated with antibiotics. Pneumococcal capsular antibody Detection was as specific (85%) as Antigen Detection, but had a lower sensitivity (50%). CONCLUSION: Pneumococcal Antigen Detection in sputum or pleural fluid is of value in making a rapid diagnosis and provides an additional diagnostic result in patients with pneumococcal pneumonia, especially those receiving antibiotic treatment.
Diane S. Leland - One of the best experts on this subject based on the ideXlab platform.
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Viral Antigen Detection
Clinical Virology Manual, 2016Co-Authors: Diane S. Leland, Ryan F. RelichAbstract:Laboratorians continually seek methodologies that yield accurate results in a timely fashion, are cost effective, and require less technical expertise. Diagnosis of viral infections via viral Antigen Detection methods such as immunofluorescence (FA), immunochromatography (lateral flow) (IC), and enzyme immunoassays (EIA) offer many of these attractive features and are useful for direct Detection of viral Antigens in an array of clinical specimens and for identification of cultivated viruses. Whether the Detection method is FA, rapid IC, or EIA, Detection of Antigens of the common respiratory viruses (i.e., adenovirus; influenza virus [Flu] A and B; parainfluenza virus [PIV] −1, −2, and −3 and respiratory syncytial virus [RSV]), has been shown to be more useful in patient management than either traditional virus isolation (1, 2, 3) or viral Detection in rapid culture using centrifugation-enhanced inoculation (4). There is considerable variability in the sensitivity, specificity, technical considerations, and turnaround time among the various methods, and each method may perform differently depending on the viral target. This chapter deals with principles of FA, IC, and EIA and their contemporary applications in viral Antigen Detection.
Dennis L. Wegner - One of the best experts on this subject based on the ideXlab platform.
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Proper Evaluation of Rapid Antigen Detection Methods for Diagnosing Streptococcal Pharyngitis
Archives of pediatrics & adolescent medicine, 1996Co-Authors: Dennis L. WegnerAbstract:THROAT CULTURING has many variables, especially the media used and the atmosphere of incubation, that affect the sensitivity of the culture method used as the reference method to evaluate a given streptococcal Antigen Detection system. A study of an Antigen Detection system that does not consider these might be biased. If a study uses an insensitive "gold standard" culture method to evaluate a rapid method, this can result in the Antigen Detection system being evaluated erroneously to appear to be as sensitive as and, possibly, a valid substitute for the more time-consuming throat cultures. In a study reported in this issue, Schlager et al 1 paid careful attention to the complexities of throat culture techniques to conduct a thorough evaluation of a new optical immunoassay for the direct Detection of group A β-hemolytic streptococci (GABHS) Antigen in throat specimens. Because our article 2 and most of the studies cited in
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Insensitivity of Rapid Antigen Detection Methods and Single Blood Agar Plate Culture for Diagnosing Streptococcal Pharyngitis
JAMA, 1992Co-Authors: Dennis L. Wegner, David L. Witte, Robert D. SchrantzAbstract:Objective. —To compare the sensitivity of five group A streptococcal Antigen Detection systems and single blood agar plate culture with a two-plate culture method for diagnosis of streptococcal pharyngitis. Design. —Two simultaneous throat swabs were obtained from consecutive patients with suspected streptococcal pharyngitis. One swab was tested for streptococcal Antigen by physicians' office nurses and the other was cultured on both aerobic blood agar and anaerobic trimethoprim-sulfamethoxazole blood agar plates. Setting. —Community office practice and community hospital laboratory. Participants. —Consecutive outpatients seen by one of four pediatricians or a family practice physician. Main Outcome Measures. —Results of rapid streptococcal Antigen tests were compared with culture results either on a single aerobic blood agar plate or on the two-plate culture method. Results. —On throat swabs from 755 consecutive outpatients, the two-plate culture method detected 261 cases (defined as 100%) of group A streptococcal pharyngitis. The anaerobic trimethoprim-sulfamethoxazole plate alone, read at 1 and 2 days, detected 245 cases (94%). The blood agar plate used alone detected 189 cases (72%) at 2 days and 151 cases (58%) at 1 day. Antigen Detection test results were positive for 106 throat specimens (41%), with individual kit sensitivity ranging from 31% to 50% compared with the two-plate culture method. Antigen Detection test sensitivity decreased with decreasing colony counts. Antigen kit false-positivity rates varied from 0 to 28%. Conclusions. —We conclude that the single blood agar plate culture and the Antigen Detection tests are insensitive, possibly leading the physician toward undertreatment and risking immunologic, local, or distant sequelae. The two-plate culture method should be the standard of practice to rule out streptococcal pharyngitis. JAMA . 1992;267:695-697
Viviane Fongaro Botosso - One of the best experts on this subject based on the ideXlab platform.
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Rapid Antigen Detection test for respiratory syncytial virus diagnosis as a diagnostic tool
Jornal de Pediatria (Versão em Português), 2017Co-Authors: Flávio Da Silva Mesquita, Daniela Crema, Célia Miranda Nunes Pinez, Thaís Cristina Colmanetti, Alfredo Elias Gilio, S. E. Vieira, Luciano M. Thomazelli, Marina Baquerizo Martinez, Danielle Bruna Leal De Oliveira, Viviane Fongaro BotossoAbstract:Objective: The aim of this study was to evaluate the QuickVue® RSV Test Kit (QUIDEL Corp, CA, USA) as a screening tool for respiratory syncytial virus in children with acute respiratory disease in comparison with the indirect immunofluorescence assay as gold standard. In Brazil, rapid Antigen Detection tests for respiratory syncytial virus are not routinely utilized as a diagnostic tool, except for the diagnosis of dengue and influenza. Methods: The authors retrospectively analyzed 486 nasopharyngeal aspirate samples from children under age 5 with acute respiratory infection, between December 2013 and August 2014, the samples were analyzed by IFI and QuickVue® RSV Test kit. Samples with discordant results were analyzed by RT‐qPCR and nucleotide sequencing. Results: From 313 positive samples by immunofluorescence assays, 282 (90%) were also positive by the rapid Antigen Detection test, two were positive only by rapid Antigen Detection test, 33 were positive only by immunofluorescence assays, and 171 were positive by both methods. The 35 samples with discordant results were analyzed by RT‐qPCR; the two samples positive only by rapid Antigen Detection test and the five positive only by immunofluorescence assays were also positive by RT‐qPCR. There was no relation between the negativity by QuickVue® RSV Test and viral load or specific strain. The QuickVue® RSV Test showed sensitivity of 90%, specificity of 98.8%, PPV of 99.3%, and negative predictive value of 94.6%, with accuracy of 93.2% and agreement κ index of 0.85 in comparison to IFA. Conclusions: This study demonstrated that the QuickVue® RSV Test Kit can be effective in early Detection of Respiratory syncytial virus in nasopharyngeal aspirate and is reliable for use as a diagnostic tool in pediatrics
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Rapid Antigen Detection test for respiratory syncytial virus diagnosis as a diagnostic tool
Jornal De Pediatria, 2016Co-Authors: Flavio S. Mesquita, Daniela Crema, Célia Miranda Nunes Pinez, Thaís Cristina Colmanetti, Alfredo Elias Gilio, S. E. Vieira, Luciano M. Thomazelli, Danielle Bruna Leal Oliveira, Marina Baquerizo Martinez, Viviane Fongaro BotossoAbstract:Abstract Objective The aim of this study was to evaluate the QuickVue ® RSV Test Kit (QUIDEL Corp, CA, USA) as a screening tool for respiratory syncytial virus in children with acute respiratory disease in comparison with the indirect immunofluorescence assay as gold standard. In Brazil, rapid Antigen Detection tests for respiratory syncytial virus are not routinely utilized as a diagnostic tool, except for the diagnosis of dengue and influenza. Methods The authors retrospectively analyzed 486 nasopharyngeal aspirate samples from children under age 5 with acute respiratory infection, between December 2013 and August 2014, the samples were analyzed by indirect immunofluorescence assay and QuickVue ® RSV Test kit. Samples with discordant results were analyzed by real time PCR and nucleotide sequencing. Results From 313 positive samples by immunofluorescence assays, 282 (90%) were also positive by the rapid Antigen Detection test, two were positive only by rapid Antigen Detection test, 33 were positive only by immunofluorescence assays, and 171 were positive by both methods. The 35 samples with discordant results were analyzed by real time PCR; the two samples positive only by rapid Antigen Detection test and the five positive only by immunofluorescence assays were also positive by real time PCR. There was no relation between the negativity by QuickVue ® RSV Test and viral load or specific strain. The QuickVue ® RSV Test showed sensitivity of 90%, specificity of 98.8%, predictive positive value of 99.3%, and negative predictive value of 94.6%, with accuracy of 93.2% and agreement κ index of 0.85 in comparison to immunofluorescence assay. Conclusions This study demonstrated that the QuickVue ® RSV Test Kit can be effective in early Detection of Respiratory syncytial virus in nasopharyngeal aspirate and is reliable for use as a diagnostic tool in pediatrics.