Sensitivity and specificity of rapid influenza testing of children in a community setting

Please cite this paper as: Stebbins et al. (2011) Sensitivity and specificity of rapid influenza testing of children in a community setting. Influenza and Other Respiratory Viruses 5(2), 104–109. Introduction Rapid influenza testing (RFT) allows for a rapid point‐of‐care diagnosis of influenza. The Quidel QuickVue^® Influenza A+B test (QuickVue) has a reported manufacturer’s sensitivity and specificity of 73% and 96%, respectively, with nasal swabs. However, investigators have shown sensitivities ranging from 22% to 77% in community settings. Methods The QuickVue rapid influenza test was evaluated in a population of elementary (K‐5) school children, using testing in the home, as part of the Pittsburgh Influenza Prevention Project during the 2007–2008 influenza season. The QuickVue test was performed with nasal swab in full accordance with package instructions and compared with the results of nasal swab semi‐quantitative RT‐PCR. Results Sensitivity of the QuickVue was found to be 27% in this sample. There was no statistically valid correlation between the semi‐quantitative PCR result and the QuickVue result. Conclusions This study is consistent with the low sensitivity of the QuickVue test also reported by others. Viral load, technique, and the use of nasal swabs were examined as contributing factors but were not found to be explanations for this result. Community testing includes patients who are on the lower spectrum of illness which would not be the case in hospital or clinic samples. This suggests that RFT is less sensitive for patients at the lower spectrum of illness, with less severe disease.     

Evaluation of immunochromatography method for rapid detection of influenza A and B viruses

We have evaluated a new rapid detection kit for influenza A and B viruses, known as the QuickVue Influenza test (Quidel Coporation, USA); which is based on immunochromatography using virus isolates and clinical specimens. Twelve strains of influenza A and B were tested for evaluate the reactivity and detection limits of this test. The QuickVue Influenza test showed a positive result for all twelve strains of influenza virus and a negative result for fourteen different kinds of other respiratory viruses. The detection limits for six strains were 5 to 30 pfu/ml for a cell culture, 1.0 x 10(3) to 6.0 x 10(4) pfu/ml for 1st PCR, 1 to 50 pfu/ml for nested PCR, 3.0 x 10(5) to 6.0 x 10(5) pfu/ml for the QuickVue Influenza test, 1.5 x 10(5) to 1.0 x 10(6) pfu/ml for the Directigen Flu A, and 7.5 x 10(5) to 5.0 x 10(6) pfu/ml for the FLU OIA. Furthermore, the QuickVue Influenza test were clinically evaluated using 92 throat swab specimens collected from patients with influenza-like illnesses. By cell culture, influenza viruses were detected in 49 of the 92 specimens (AH1N1: 20, AH3N2: 7, B: 22); the titers of the influenza viruses were between 2.5 pfu/ml and 7.0 x 10(5) pfu/ml. Compared to cell culture, the QuickVue Influenza test showed a sensitivity of 75.5%, a specificity of 93.0%, a positive predictive value of 92.5%, a negative predictive value of 76.9%, and an efficiency value of 83.7%. On the other hand, influenza viruses were detected in 54 of the 92 specimens (AH1N1: 19, AH 3N2: 10, B: 25) by RT-PCR. Compared to RT-PCR, the QuickVue Influenza test showed a sensitivity of 72.2%, a specificity of 97.4%, a positive predictive value of 97.5%, a negative predictive value of 71.2%, and an efficiency value of 82.6%. Overall, only one throat swab specimen produced a false positive result using the QuickVue Influenza test; thus, this test appears to have a high specificity. We conclude that the QuickVue Influenza test is a simple one-step test with a sensitivity and specificity equivalent to those of other conventional diagnostic kits. The test is useful and suitable for the diagnosis of influenza and for identifying influenza patients requiring antiviral therapy.     

The prevalance of respiratory viruses among healthcare workers serving pilgrims in Makkah during the 2009 influenza A (H1N1) pandemic

Despite the high risk of acquiring respiratory infections, healthcare workers who treat pilgrims at Hajj have not been studied in previous research on respiratory diseases during Hajj. The objective of this study was to determine the prevalence of different respiratory viruses among healthcare workers who treated pilgrims during Hajj 2009, the year of the influenza A H1N1 pandemic. A cross-sectional study was performed just before and after Hajj (25-29 November, 2009). Nasal and throat swabs were tested for 18 respiratory virus types and subtypes. A total of 184 healthcare workers were examined. Most were men (85%) with an average age of 41 years. Before the Hajj, rates of seasonal influenza vaccination were higher (51%) than rates of pandemic influenza A H1N1 vaccination (22%). After the Hajj, participants reported high rates of maintaining hand hygiene (98%), cough etiquette (89%), and wearing a face mask (90%). Among all the viruses tested, only two were detected: rhinovirus was detected in 12.6% and Coronavirus 229E in 0.6%. Rhinovirus was detected in 21% of those who had respiratory symptoms during Hajj. Influenza A (including H1N1), influenza B. respiratory syncytial virus, other coronaviruses, parainfluenza viruses, human metapneumovirus, adenovirus, and human bocavirus were not detected. The finding of high rates of rhinovirus infection corresponds to their frequent occurrence in adults. None of the participants had influenza A H1N1 2009, possibly because it was also infrequent among the 2009 pilgrims.     

Pandemic 2009 influenza A (H1N1) infection among 2009 Hajj Pilgrims from Southern Iran: a real‐time RT‐PCR‐based study

Please cite this paper as: Ziyaeyan et al. (2012) Pandemic 2009 influenza A H1N1 infection among 2009 Hajj Pilgrims from Southern Iran: a real‐time RT‐PCR‐based study. Influenza and Other Respiratory Viruses 6(601), e80–e84. Background Hajj is a mass gathering undertaken annually in Mecca, Saudi Arabia. The 2009 Hajj coincided with both the pandemic influenza A/H1N1 2009 (A(H1N1)pdm09) and seasonal types of influenza A viruses. The interaction between pandemic influenza and Hajj could cause both a high level of mortality among the pilgrims and the spread of infection in their respective countries upon their return home. Objective The present study attempted to determine the point prevalence of A(H1N1)pdm09 among returning Iranian pilgrims, most of whom had been vaccinated for seasonal influenza but not A(H1N1)pdm09. Methods Pharyngeal swabs were collected from 305 pilgrims arriving at the airport in Shiraz, Iran. RNA was extracted from the samples and A(H1N1)pdm09 and other seasonal influenza A viruses were detected using TaqMan real‐time PCR. For A(H1N1)pdm09‐positive samples, the sensitivity to oseltamivir was also evaluated. Results Subjects included 132 (43·3%) men and 173 (56·7%) women, ranging in age from 24 to 65 years. The A(H1N1)pdm09 virus was detected in five (1·6%) pilgrims and other influenza A viruses in eight (2·6%). All the A(H1N1)pdm09 were sensitive to oseltamivir. Conclusions Only five cases were found to be positive for A(H1N1)pdm09, and it seems unlikely that the arrival of infected pilgrims to their homelands would cause an outbreak of a new wave of infection there. Thus, the low morbidity and mortality rates among the pilgrims could be attributed to the characteristics of A(H1N1)pdm09, which causes morbidity and mortality in a way similar to the seasonal influenza infections, absence of high‐risk individuals among the Iranian pilgrims, and the instructions given to them about contact and hand hygiene, and respiratory etiquette.     

Can procalcitonin tests aid in identifying bacterial infections associated with influenza pneumonia? A systematic review and meta‐analysis

Objective To summarize evidence for the diagnostic accuracy of procalcitonin (PCT) tests for identifying secondary bacterial infections in patients with influenza. Methods Major databases, including MEDLINE, EMBASE, and the Cochrane Library, were searched for studies published between January 1966 and May 2009 that evaluated PCT as a marker for diagnosing bacterial infections in patients with influenza infections and that provided sufficient data to construct two‐by‐two tables. Results Six studies were selected that included 137 cases with bacterial coinfection and 381 cases without coinfection. The area under a summary ROC curve was 0·68 (95% CI: 0·64–0·72). The overall sensitivity and specificity estimates for PCT tests were 0·84 (95% CI: 0·75–0·90) and 0·64 (95% CI: 0·58–0·69), respectively. These studies reported heterogeneous sensitivity estimates ranging from 0·74 to 1·0. The positive likelihood ratio for PCT (LR+ = 2·31; 95% CI: 1·93–2·78) was not sufficiently high for its use as a rule‐in diagnostic tool, while its negative likelihood ratio was reasonably low for its use as a rule‐out diagnostic tool (LR? = 0·26; 95% CI: 0·17–0·40). Conclusions Procalcitonin tests have a high sensitivity, particularly for ICU patients, but a low specificity for identifying secondary bacterial infections among patients with influenza. Because of its suboptimal positive likelihood ratio and good negative likelihood ratio, it can be used as a suitable rule‐out test but cannot be used as a standalone rule‐in test.     

Is there any role for rapid tests for Chlamydia trachomatis?

The main aim of this pilot study was to evaluate the sensitivity and specificity of a recently introduced rapid diagnostic test, the QuickVue chlamydia test against polymerase chain reaction (PCR) for endocervical samples. Due to concerns surrounding the low specificity of rapid tests for a low prevalence population we assessed its performance for both high and low prevalence populations. The sensitivity and specificity of the QuickVue test compared to PCR were 65% (95% confidence interval [CI] 42-87%) and 100% respectively for the high prevalence population and 25% (95% CI: 5-70%) and 100% respectively for the low prevalence population. The positive predictive value (PPV) was 100% for both high and low prevalence population. The sensitivity of the QuickVue test for a high prevalence population was comparable to laboratory-based immunoassay techniques. However, for a low prevalence population, this test did not identify one in 4 cases due to its low sensitivity and its use cannot be recommended. Although the high specificity and PPV of this test indicate that for positive results no confirmatory test would be needed, because of the small number of cases included in this pilot study, this finding needs to be explored through a larger study.     

Validation of four Helicobacter pylori rapid blood tests in a multi-ethnic Asian population

AIM: To validate the accuracy of four rapid blood tests in the diagnosis of Helicobacter pylori. METHODS: Consecutive dyspeptic patients scheduled for endoscopy at the National University Hospital, Singapore, were interviewed and had blood drawn for serology. The first 109 patients were tested with BM-test (BM), Pyloriset Screen (PS) and QuickVue (QV), and the next 99 subjects were tested with PS and Unigold (UG). Endoscopies were performed blinded to rapid blood test results and biopsies were taken for culture and rapid urease test. Urea breath tests were performed after endoscopies. The rapid blood test results were compared with four reference tests (rapid urease test, culture, serology, and breath test). RESULTS: The study population composed of 208 patients (mean age 43.1 years; range 18-73 years; 119 males; 174 Chinese). The number of evaluable patients for BM, QV, UG and PS were 102, 102, 95, and 197, respectively. The sensitivity and specificity, respectively were: PS 80.2%, 95.8%; UG 55.9%, 100%; QV 43.3%, 100%; BM 67.2%, 97.1%. CONCLUSION: The rapid blood test kits showed high specificity and positive predictive value (97-100%), while sensitivity and negative predictive value ranged widely (43%-80% and 47%-73%, respectively). Among test kits, PS showed the best sensitivity (80%), best negative predictive value (73%) and best negative likelihood ratio (0.207). PS had a specificity of 96%, positive predictive value of 97% and positive likelihood ratio of 19.1.     

High risk of Mycobacterium tuberculosis infection during the Hajj pilgrimage

INTRODUCTION: Annually more than 2 million pilgrims from all over the world attend the Hajj in Saudi Arabia. Overcrowding during this pilgrimage leads to a high risk of transmission of airborne infectious diseases. Tuberculosis (TB) is common among hospitalized pilgrims, but the overall risk of acquiring Mycobacterium tuberculosis infection during this pilgrimage is not known. We conducted a prospective study to assess the risk of M. tuberculosis infection among Hajj pilgrims. METHODS: We measured the immune response to TB antigens using a whole-blood assay (QuantiFERON TB assay) prior to departure and 3 months after return from the Hajj pilgrimage. RESULTS: Of 357 paired assays, 149 pilgrims were negative prior to the Hajj and 15 (10%) of these had a significant rise in immune response to TB antigens. CONCLUSIONS: Pilgrims may be at high risk of acquiring M. tuberculosis infection during the Hajj. This has significant public health implications for TB control in countries with large Muslim populations.     

Comparison of three rapid diagnostic kits using immunochromatography for detection of influenza A virsuses

In 2004, 3 new rapid influenza diagnostic kits using immunochromatography that allow type differentiation became commercially available. They are the ESPLINE Influenza A & B-N (Fujirebio Corp., Japan: ESPLINE-N hereafter), QuickVue Rapid SP influ (Quidel Corp., USA: QuickVue), and POCTEM INFLUENZA A/B (INTERNATIONAL REAGENTS Corp., Japan: POCTEM). The authors performed a prospective study that compared the usefulness among the 3 kits in 151 children with suspected influenza, who were examined within 3 days after onset, between January and March, 2004. Nasopharyngeal aspirates were collected, and viruses were isolated. The residual samples were diluted and centrifuged, and the supernatant was used for the rapid diagnosis tests. Influenza virus AH3 was isolated in 95 children and influenza B virus in 3. In the 95 children with influenza virus AH3, the sensitivity and specificity of ESPLINE-N were 100% and 100%, respectively, those of QuickVue were 99% and 91%, and those of POCTEM were 91% and 100%. The sensitivity of POCTEM was significantly lower than that of the other 2 kits (p < 0.01), and the specificity of QuickVue was significantly lower than that of the other 2 kits (p < 0.05). Examination was performed within 1 day after onset in 55 of the 95 children, including 30 who underwent examination within 6 hours after the development of fever. The body temperature was less than 38.0 degrees C in 14 of the 95 children. In all children including these children, virus detection was possible by ESPLINE-N. ESPLINE-N allowed very accurate diagnosis of influenza A using samples prepared by diluting and centrifuging nasopharyngeal aspirates.     

Meningococcal W135 carriage; enhanced surveillance amongst east London Muslim pilgrims and their household contacts before and after attending the 2002 Hajj

BACKGROUND: For two successive years, 2000 and 2001, there was a world-wide outbreak of W135 meningococcal disease amongst pilgrims who attended the Hajj and in their contacts after returning home. METHODS: Beginning January 2002, we offered meningococcal quadrivalent polysaccharide vaccine (against serogroups A, C, Y and W135) to pilgrims and collected a throat swab for meningococcal W135 carriage before and after their pilgrimage. RESULTS: The overall Neisseria meningitidis carriage pre-Hajj was 8.3% and 6.3% post-Hajj. We found W135 carriage rates of 0.8% before and 0.6% after Hajj, respectively. 21% (36/174) of the pilgrims were treated with antibiotics for respiratory illness. CONCLUSION: The carriage of meningococcus W135 among UK pilgrims who visited the Hajj in 2002 was low. This contrasts with another study suggesting pilgrims frequently acquired N. meningitidis W135 carriage during 2001 Hajj. The use of the quadrivalent vaccine may account for this difference.     

呼出气一氧化氮对慢性咳嗽人群中咳嗽变异型哮喘的诊断价值:Meta分析

目的 咳嗽变异型哮喘(cough variant asthma,CVA)是慢性咳嗽的常见病因.本研究旨在应用Meta分析的方法评价呼出气一氧化氮(fractional exhaled nitric oxide,FeNO)检测对慢性咳嗽人群CVA诊断的有效性和准确性.方法 检索Embase、PubMed、Medline、Cochrane library、Web of science、百度学术、中国期刊网和万方数据库,全面收集FeNO在慢性咳嗽人群对CVA诊断的文献,检索时限均从建库至2016年8月.根据QUADAS-2量表的评价标准对文献进行质量评价.用Stata 14.0、RevMan 5.0软件对文献进行异质性分析,并计算合并的敏感性、特异性、阳性似然比、阴性似然比、诊断优势比和SROC曲线下面积.结果 共纳入文献5篇,涉及慢性咳嗽患者704例.FeNO检测诊断CVA合并的敏感度、特异度、阳性似然比、阴性似然比、诊断优势比、SROC曲线下面积分别为0.74 [95％可信区间(CI):0.69～0.79],0.85 (95％ CI:0.81～0.88),4.73 (95％CI:3.70～6.05),0.31 (95％ CI:0.26～0.38),14.84 (95％CI:10.11～21.79)和0.87 (95％CI:0.84～0.89).结论 FeNO对慢性咳嗽人群中CVA的诊断有较好的敏感度和特异度,可作为重要的诊断指标.     

Acute respiratory tract infections among Hajj medical mission personnel, Saudi Arabia.

OBJECTIVES: To estimate the prevalence of acute respiratory tract infections (ARI) among 250 personnel serving in a Hajj medical mission, Al-Hada and Taif Armed Forces Hospitals, during the 2005 season and to determine the effectiveness of protective measures, including influenza vaccination, for these infections. METHODS: This was a nested case-control study. A questionnaire was distributed to the study cohort two weeks after the Hajj period and was self-administered by all recruited subjects. In addition, the medical records of study subjects were reviewed at Al-Hada Hospital for the same period in order to document ARI. RESULTS: The attack rate for ARI among study subjects during Hajj season or within two weeks of returning was 25.6% (64/250). Logistic regression analysis of factors related to acquiring ARI revealed that contact with pilgrims imposed an extremely high risk of infection (adjusted OR 13.2, 95% CI 1.5-117.6). Moreover, non-use of alcohol-based hand disinfection carried a more than 8-fold risk of acquiring ARI compared to those who always used alcohol for hand disinfection (adjusted OR 8.4, 95% CI 2.2-32.2). Smoking was also a predictor of ARI in our cohort and influenza vaccination was associated with a 30% reduction in ARI compared to unvaccinated subjects, although this finding was not statistically significant. Unexpectedly, the logistic regression model showed that Saudi nationals were three times more likely to acquire ARI than non-Saudis (adjusted OR 3.1, 95% CI 1.2-8.4). CONCLUSIONS: The common practice among pilgrims and medical personnel of using surgical facemasks to protect themselves against ARI should be discontinued and regular use of alcohol-based hand scrubs should be more vigorously encouraged. Further research is needed to evaluate the protective value of N95 facemasks against ARI during the Hajj period.     

Health risks at the Hajj

Annually, millions of Muslims embark on a religious pilgrimage called the "Hajj" to Mecca in Saudi Arabia. The mass migration during the Hajj is unparalleled in scale, and pilgrims face numerous health hazards. The extreme congestion of people and vehicles during this time amplifies health risks, such as those from infectious diseases, that vary each year. Since the Hajj is dictated by the lunar calendar, which is shorter than the Gregorian calendar, it presents public-health policy planners with a moving target, demanding constant preparedness. We review the communicable and non-communicable hazards that pilgrims face. With the rise in global travel, preventing disease transmission has become paramount to avoid the spread of infectious diseases, including SARS (severe acute respiratory syndrome), avian influenza, and haemorrhagic fever. We examine the response of clinicians, the Saudi Ministry of Health, and Hajj authorities to these unique problems, and list health recommendations for prospective pilgrims.     

Diagnostic accuracy of EUS for vascular invasion in pancreatic and periampullary cancers: a meta-analysis and systematic review

BACKGROUND: Vascular invasion (VI) in a patient with pancreatic or periampullary cancers precludes surgery and indicates a poor prognosis. Published data on the accuracy of EUS in diagnosing VI is varied. OBJECTIVE: The aim of this meta-analysis was to evaluate the accuracy of EUS in diagnosing VI in patients with pancreatic and periampullary cancers. DESIGN: Data from EUS studies were pooled according to the Mantel-Haenszel and DerSimonian Laird methods. PATIENTS: EUS studies in which VI was confirmed by surgery or angiography were selected. INTERVENTIONS: EUS. MAIN OUTCOME MEASURES: Pooled estimates of sensitivity, specificity, likelihood ratios, and diagnostic odds ratio of EUS. RESULTS: Data were extracted from 29 studies (N = 1308) that met the inclusion criteria. The pooled sensitivity of EUS in diagnosing VI was 73% (95% CI, 68.8-76.9) and the pooled specificity was 90.2% (95% CI, 87.9-92.2). The positive likelihood ratio for diagnosing VI by EUS was 9.1 (95% CI, 4.6-17.9) and the negative likelihood ratio was 0.3 (95% CI, 0.2-0.5). Diagnostic odds ratio, the odds of having VI in positive as compared with negative EUS studies, was 40.1 (95% CI, 16.1-99.9). The P value for chi(2) heterogeneity for all the pooled estimates was >.05. CONCLUSIONS: Although EUS is the best noninvasive test to diagnose VI in pancreatic and periampullary cancers, this meta-analysis showed that the specificity (90%) is high but the sensitivity (73%) is not as high as suggested. Further refinements in EUS technologies and interpretation may improve the sensitivity for detecting VI.     

简化Geneva评分联合年龄校正的D-二聚体对肺血栓栓塞症的诊断预测价值

目的:探讨简化Geneva评分(SGS)、年龄校正的D-二聚体(AADD)及二者联合对肺血栓栓塞症(PTE)的诊断预测价值。方法:研究对象为山西医科大学第一医院2016年12月至2017年12月疑似诊断为PTE住院患者102例。对所有纳入患者进行SGS评分并收集其AADD,以CT肺动脉造影和/或核素肺通气/血流灌注阳性结果作为确诊PTE的金标准,计算SGS、AADD及SGS联合AADD对PTE诊断的敏感度、特异度、阳性预测值、阴性预测值、阳性似然比、阴性似然比、约登指数,并分析三者对PTE的诊断预测价值。结果:102例疑诊PTE患者中确诊PTE者31例(30.4%),排除PTE者71例(69.6%)。SGS在诊断PTE中敏感度为80.6%,特异度为76.1%,阳性预测值为59.5%,阴性预测值为90.0%,阳性似然比为3.37,阴性似然比为0.25,约登指数为0.567;AADD在诊断PTE中敏感度为93.5%,特异度为63.4%,阳性预测值为52.7%,阴性预测值为95.7%,阳性似然比为2.55,阴性似然比为0.10,约登指数为0.569;SGS联合AADD在诊断PTE中敏感度为92.0%,特异度为90.4%,阳性预测值为82.1%,阴性预测值为95.9%,阳性似然比为9.58,阴性似然比为0.09,约登指数为0.824。结论:SGS联合AADD可明显提高PTE诊断效能,其阴性预测价值与阳性预测价值均高于单独使用时。     

Evaluation of an immunochromatography test using enzyme immunoassay for rapid detection of influenza A and B viruses

We evaluated the performance of an improved version of Espline Influenza A & B-N (Fujirebio Inc., Japan), an immunochromatography test using enzyme immunoassay for rapid diagnosis of influenza A and B. The test produced positive results for four strains of influenza viruses and thirty-one influenza viral antigens and negative results for all of thirty strains of other respiratory viruses that were tested. The detection limit of this test was 5.8 x 10(2) to 5.8 x 10(3) pfu/assay, which is more sensitive than the old version of Espline. Furthermore, 715 respiratory specimens collected from the patients (children, 79.4%; adults, 18.5%; unknown, 2.1%) with influenza-like illnesses during the 2002/2003 influenza season in Japan were tested as part of a clinical evaluation of this test. The relative performance of this test compared to cell culture and nested RT-PCR results were examined. In the cell cultures, influenza viruses were detected in 488 of the 715 specimens (overall, 68.3%; AH3, 41.7%; B, 26.4%; AH3 and B, 0.1%). For influenza A, the sensitivity of this test was 95.4% (125/131) for nasal aspirates, 96.8% (92/95) for nasal swabs, and 85.1% (63/74) for throat swabs. For influenza B, the sensitivity of this test was 91.2% (52/57) for nasal aspirates, 88.1% (59/67) for nasal swabs, and 71.6% (48/67) for throat swabs. The new test exhibited a remarkably higher sensitivity to influenza A in throat swabs than the old version of Espline. Only two false positive results were obtained out of a total of 223 virus negative specimens; the specificity of the test was 100% (88/88) for nasal aspirates, 97.6% (81/83) for nasal swabs, and 100% (52/52) for throat swabs. We conclude that the new Espline Influenza A&B-N rapid diagnostic test is easy to use and has a high sensitivity and specificity, especially for influenza A.