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Accurate detection of Helicobacter pylori and its antimicrobial resistance is essential for eradication of the infections. The aim of this study was to compare five different CE‐IVD marked assays in detection of H. pylori from 268 clinical stool samples. Samples were considered positive for H. pylori when at least three of the five tests were positive. Amplified IDEIA Hp StAR (Oxoid) and Premier Platinum HpSA PLUS (Meridian Bioscience Inc.) assays showed sensitivity of 100% [95% CI (confidence interval): 87–100] and LIAISON® Meridian H. pylori SA (DiaSorin) of 83.3% (95% CI: 66–93). Specificities of the assays were 94.5% (95% CI: 91–97), 95.4%; (95% CI: 92–97), and 97.1% (95% CI: 94–99) respectively. Amplidiag® H. pylori + ClariR (Mobidiag) assay showed 93.3% (95% CI: 78–99) and Allplex™ H. pylori & ClariR Assay (Seegene Inc.) 36.7% (95% CI: 22–55) sensitivity, while specificity of both was 97.9% (95% CI: 95–99). The Amplidiag® and Allplex™ assays concordantly detected clarithromycin resistance in positive for H. pylori samples. The Amplidiag® assay showed the highest accuracy, namely 97.4% (95% CI: 95–99). These data provide helpful information for planning laboratory diagnostics of H. pylori and detection of clarithromycin resistance from stool samples. [ABSTRACT FROM AUTHOR]

Abstract Background Dirofilaria immitis, commonly known as heartworm (HW), is a parasitic nematode transmitted by various mosquito species, leading to heartworm disease (HWD) in dogs. Diagnosis of HW typically involves antigen or microfilariae detection, or visualization of adult worms through imaging or post mortem examination. Polymerase chain reaction (PCR) and micro RNA (miRNA) detection have been explored for HW diagnosis. Methods Three dogs, previously experimentally infected with HW, underwent blood sampling every 4 weeks for 7 months. Samples were assessed for antigen presence after heat treatment, PCR amplification, and microfilaria examination using Giemsa-stained thick smears. Additionally, whole blood aliquots underwent miRNA deep sequencing and bioinformatic analysis. Results Heartworm antigen was detectable after heat treatment at 20 weeks post-inoculation and via PCR at 24 weeks, with microfilariae observed in peripheral blood smears at 28 weeks. However, deep miRNA sequencing revealed that the miRNA candidate sequences are not consistently expressed before 28 weeks of infection. Conclusions While ancillary molecular methods such as PCR and miRNA sequencing may be less effective than antigen detection for detecting immature larval stages in an early stage of infection, our experimental findings demonstrate that circulating miRNAs can still be detected in 28 weeks post-infection. Graphical Abstract

Background: Dirofilaria immitis, commonly known as heartworm (HW), is a parasitic nematode transmitted by various mosquito species, leading to heartworm disease (HWD) in dogs. Diagnosis of HW typically involves antigen or microfilariae detection, or visualization of adult worms through imaging or post mortem examination. Polymerase chain reaction (PCR) and micro RNA (miRNA) detection have been explored for HW diagnosis. Methods: Three dogs, previously experimentally infected with HW, underwent blood sampling every 4 weeks for 7 months. Samples were assessed for antigen presence after heat treatment, PCR amplification, and microfilaria examination using Giemsa-stained thick smears. Additionally, whole blood aliquots underwent miRNA deep sequencing and bioinformatic analysis. Results: Heartworm antigen was detectable after heat treatment at 20 weeks post-inoculation and via PCR at 24 weeks, with microfilariae observed in peripheral blood smears at 28 weeks. However, deep miRNA sequencing revealed that the miRNA candidate sequences are not consistently expressed before 28 weeks of infection. Conclusions: While ancillary molecular methods such as PCR and miRNA sequencing may be less effective than antigen detection for detecting immature larval stages in an early stage of infection, our experimental findings demonstrate that circulating miRNAs can still be detected in 28 weeks post-infection. [ABSTRACT FROM AUTHOR]

BACKGROUND: The aim of this study was to determine the distribution of rotavirus and adenovirus in pediatric patients evaluated for viral gastroenteritis in a hospital in the Eastern Province of Saudi Arabia for 22 years. MATERIALS AND METHODS: This was a retrospective study based in a secondary healthcare center in Saudi Arabia. Laboratory and demographic data were collected from hospital records for all pediatric patients (up to 14 years old) evaluated for viral gastroenteritis by rotavirus/adenovirus antigen detection kit from January 2000 to December 2022. Data were analyzed utilizing SPSS version 28.0. Categorical data were presented as frequency and percentages, whereas mean and standard deviations were computed for continuous variables. Chi-square test and t-test were used to determine statistical significance. RESULTS: The overall yields of antigen detection were 13.6% for rotavirus and 2.6% for adenovirus. Coinfection with both viruses was documented in 0.5% of the study population. Rotavirus was persistently detected in the past two decades with varying frequency, but the detection of adenovirus showed intervals of at least three consecutive years of zero confirmed cases. Before 2013, when the rotavirus vaccine was introduced in Saudi Arabia, rotavirus was much more prevalent than adenovirus (30% compared to 3.8% in 2010), but they became equally prevalent a decade after the introduction of the vaccine. Rotavirus gastroenteritis showed three different peaks in the year, in March, July, and December. Each peak was followed by a gradual decrease in prevalence before the next peak. Adenovirus, in contrast, was detected consistently around the year at rates between 2% and 5%. CONCLUSION: Rotavirus and adenovirus gastroenteritis have changed in prevalence in the past two decades. We found distinct seasonal patterns associated with rotavirus and adenovirus gastroenteritis. The utilization of virological testing for pediatric gastroenteritis with syndromic testing panels is to be encouraged to improve the knowledge of the true prevalence of enteric viruses.

Abstract Background During the COVID-19 pandemic, antigen diagnostic tests were frequently used for screening, triage, and diagnosis. Novel instrument-based antigen tests (iAg tests) hold the promise of outperforming their instrument-free, visually-read counterparts. Here, we provide a systematic review and meta-analysis of the SARS-CoV-2 iAg tests’ clinical accuracy. Methods We systematically searched MEDLINE (via PubMed), Web of Science, medRxiv, and bioRxiv for articles published before November 7th, 2022, evaluating the accuracy of iAg tests for SARS-CoV-2 detection. We performed a random effects meta-analysis to estimate sensitivity and specificity and used the QUADAS-2 tool to assess study quality and risk of bias. Sub-group analysis was conducted based on Ct value range, IFU-conformity, age, symptom presence and duration, and the variant of concern. Results We screened the titles and abstracts of 20,431 articles and included 114 publications that fulfilled the inclusion criteria. Additionally, we incorporated three articles sourced from the FIND website, totaling 117 studies encompassing 95,181 individuals, which evaluated the clinical accuracy of 24 commercial COVID-19 iAg tests. The studies varied in risk of bias but showed high applicability. Of 24 iAg tests from 99 studies assessed in the meta-analysis, the pooled sensitivity and specificity compared to molecular testing of a paired NP swab sample were 76.7% (95% CI 73.5 to 79.7) and 98.4% (95% CI 98.0 to 98.7), respectively. Higher sensitivity was noted in individuals with high viral load (99.6% [95% CI 96.8 to 100] at Ct-level ≤ 20) and within the first week of symptom onset (84.6% [95% CI 78.2 to 89.3]), but did not differ between tests conducted as per manufacturer’s instructions and those conducted differently, or between point-of-care and lab-based testing. Conclusion Overall, iAg tests have a high pooled specificity but a moderate pooled sensitivity, according to our analysis. The pooled sensitivity increases with lower Ct-values (a proxy for viral load), or within the first week of symptom onset, enabling reliable identification of most COVID-19 cases and highlighting the importance of context in test selection. The study underscores the need for careful evaluation considering performance variations and operational features of iAg tests.

Objectives: Rapid management of patients with respiratory tract infections in hospital emergency departments is one of the main objectives since the concurrent circulation of respiratory viruses following the SARS-CoV-2 pandemic. The use of new combined point-of-care antigen tests for detecting influenza A/B and SARS-CoV-2 represents an advantage in response time over the molecular tests. The objective was to evaluate the suitability of the CLINITEST® Rapid Covid-19 + Influenza Antigen test (Siemens Healthineers, Germany) (RCIA test) by measuring the sensitivity, specificity, Cohen's kappa, and cut-off values. Methods: Nasopharyngeal samples were collected from a randomised group of symptomatic patients of all ages at emergency department during January–February 2023. In parallel, these patients were screened for influenza A/B, and SARS-CoV-2 using RT-PCR. The Ct (cycle threshold) values were collected for positive [RT-PCR (+) /RCIA test (+)] and false negative [(RT-PCR (+) /RCIA test (-)] samples. A subanalysis was performed in the paediatric population (< 16 years-old). Results: We included 545 patients (55.8% females) with a median age of 7 years-old (IQR: 1–66.5). The RCIA test showed a sensitivity of 59.7% [95%CI: 46.9–67.33] for influenza A, 65.6% [95%CI: 49.5–80.3] for influenza B, and 76.9% [95%CI: 45.8–84.8] for SARS-CoV-2. The specificity was between 90.7%-99.7% with a moderate/high level of agreement with RT-PCR (kappa score: 0.6–0.8) for the three respiratory viruses included in the RCIA test. Conclusions: The sensitivity of the RCIA test is insufficient for screening of patients, including patients with low Ct values (Ct > 20). Despite its good specificity and Cohen's kappa value, its use as a screening test is not comparable to RT-PCR systems in the ED environment with a high number of false negative results. [ABSTRACT FROM AUTHOR]

Background: During the COVID-19 pandemic, antigen diagnostic tests were frequently used for screening, triage, and diagnosis. Novel instrument-based antigen tests (iAg tests) hold the promise of outperforming their instrument-free, visually-read counterparts. Here, we provide a systematic review and meta-analysis of the SARS-CoV-2 iAg tests' clinical accuracy. Methods: We systematically searched MEDLINE (via PubMed), Web of Science, medRxiv, and bioRxiv for articles published before November 7th, 2022, evaluating the accuracy of iAg tests for SARS-CoV-2 detection. We performed a random effects meta-analysis to estimate sensitivity and specificity and used the QUADAS-2 tool to assess study quality and risk of bias. Sub-group analysis was conducted based on Ct value range, IFU-conformity, age, symptom presence and duration, and the variant of concern. Results: We screened the titles and abstracts of 20,431 articles and included 114 publications that fulfilled the inclusion criteria. Additionally, we incorporated three articles sourced from the FIND website, totaling 117 studies encompassing 95,181 individuals, which evaluated the clinical accuracy of 24 commercial COVID-19 iAg tests. The studies varied in risk of bias but showed high applicability. Of 24 iAg tests from 99 studies assessed in the meta-analysis, the pooled sensitivity and specificity compared to molecular testing of a paired NP swab sample were 76.7% (95% CI 73.5 to 79.7) and 98.4% (95% CI 98.0 to 98.7), respectively. Higher sensitivity was noted in individuals with high viral load (99.6% [95% CI 96.8 to 100] at Ct-level ≤ 20) and within the first week of symptom onset (84.6% [95% CI 78.2 to 89.3]), but did not differ between tests conducted as per manufacturer's instructions and those conducted differently, or between point-of-care and lab-based testing. Conclusion: Overall, iAg tests have a high pooled specificity but a moderate pooled sensitivity, according to our analysis. The pooled sensitivity increases with lower Ct-values (a proxy for viral load), or within the first week of symptom onset, enabling reliable identification of most COVID-19 cases and highlighting the importance of context in test selection. The study underscores the need for careful evaluation considering performance variations and operational features of iAg tests. [ABSTRACT FROM AUTHOR]

BACKGROUND: The aim of this study was to determine the distribution of rotavirus and adenovirus in pediatric patients evaluated for viral gastroenteritis in a hospital in the Eastern Province of Saudi Arabia for 22 years. MATERIALS AND METHODS: This was a retrospective study based in a secondary healthcare center in Saudi Arabia. Laboratory and demographic data were collected from hospital records for all pediatric patients (up to 14 years old) evaluated for viral gastroenteritis by rotavirus/adenovirus antigen detection kit from January 2000 to December 2022. Data were analyzed utilizing SPSS version 28.0. Categorical data were presented as frequency and percentages, whereas mean and standard deviations were computed for continuous variables. Chi-square test and t-test were used to determine statistical significance. RESULTS: The overall yields of antigen detection were 13.6% for rotavirus and 2.6% for adenovirus. Coinfection with both viruses was documented in 0.5% of the study population. Rotavirus was persistently detected in the past two decades with varying frequency, but the detection of adenovirus showed intervals of at least three consecutive years of zero confirmed cases. Before 2013, when the rotavirus vaccine was introduced in Saudi Arabia, rotavirus was much more prevalent than adenovirus (30% compared to 3.8% in 2010), but they became equally prevalent a decade after the introduction of the vaccine. Rotavirus gastroenteritis showed three different peaks in the year, in March, July, and December. Each peak was followed by a gradual decrease in prevalence before the next peak. Adenovirus, in contrast, was detected consistently around the year at rates between 2% and 5%. CONCLUSION: Rotavirus and adenovirus gastroenteritis have changed in prevalence in the past two decades. We found distinct seasonal patterns associated with rotavirus and adenovirus gastroenteritis. The utilization of virological testing for pediatric gastroenteritis with syndromic testing panels is to be encouraged to improve the knowledge of the true prevalence of enteric viruses. [ABSTRACT FROM AUTHOR]

Surges of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections among health care workers (HCWs) have led to critical staffing shortages. From January 4 to February 4, 2022, we implemented a return-to-work antigen testing program for HCWs, and 870 HCWs participated. Antigen test positivity was 60.5% for those ≤5 days from symptom onset or positive polymerase chain reaction (PCR), and 47.4% were positive at day 7. Antigen positivity was associated with receiving a booster vaccination and being ≤6 days from symptom onset or PCR test, but not age or a symptomatic infection. Rapid antigen testing can be a useful tool to guide return-to-work and isolation precautions for HCWs following infection.

High-throughput and rapid screening testing is highly desirable to effectively combat the rapidly evolving COVID-19 pandemic co-presents with influenza and seasonal common cold epidemics. Here, we present a general workflow for iterative development and validation of an antibody-based microarray assay for the detection of a respiratory viral panel: (a) antibody screening to quickly identify optimal reagents and assay conditions, (b) immunofluorescence assay design including signal amplification for low viral titers, (c) assay characterization with recombinant proteins, inactivated viral samples and clinical samples, and (d) multiplexing to detect a panel of common respiratory viruses. Using RT-PCR-confirmed SARS-CoV-2 positive and negative pharyngeal swab samples, we demonstrated that the antibody microarray assay exhibited a clinical sensitivity and specificity of 77.2% and 100%, respectively, which are comparable to existing FDA-authorized antigen tests. Moreover, the microarray assay is correlated with RT-PCR cycle threshold (Ct) values and is particularly effective in identifying high viral titers. The multiplexed assay can selectively detect SARS-CoV-2 and influenza virus, which can be used to discriminate these viral infections that share similar symptoms. Such protein microarray technology is amenable for scale-up and automation and can be broadly applied as a both diagnostic and research tool.

We have engineered a cell that can be used for diagnosing active severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. Isolation of individuals with active infections offers an effective solution for mitigating pandemics. However, the implementation of this practice requires robust infrastructure for rapid and intuitive testing, which is currently missing in our communities. To address this need, we engineered a fast-growing cell line into a cell-based antigen test platform for emerging viruses, i.e., DxCell, that can be rapidly deployed in decentralized health care facilities for continuous testing. The technology was characterized using cells engineered to present spike glycoprotein of SARS-CoV-2 (SARS-CoV-2-Sgp-cells) and Calu-3 host cells infected with competent SARS-CoV-2. Preclinical validation was conducted by directly incubating the DxCell with oropharyngeal swabs from mice infected with SARS-CoV-2. No sample preparation steps are necessary. The DxCell quantitatively detected the SARS-CoV-2-Sgp-cells within 1 h (P

In this study, a cost-effective sandwich ELISA test, based on polyclonal antibodies, for routine quantification SARS-CoV-2 nucleocapsid (N) protein was developed. The recombinant N protein was produced and used for the production of mice and rabbit antisera. Polyclonal N protein-specific antibodies served as capture and detection antibodies. The prototype ELISA has LOD 0.93 ng/mL and LOQ 5.3 ng/mL, with a linear range of 1.52–48.83 ng/mL. N protein heat pretreatment (56 °C, 1 h) decreased, while pretreatment with 1% Triton X-100 increased analytical ELISA sensitivity. The diagnostic specificity of ELISA was 100% (95% CI, 91.19–100.00%) and sensitivity was 52.94% (95% CI, 35.13–70.22%) compared to rtRT-PCR (Ct < 40). Profoundly higher sensitivity was obtained using patient samples mostly containing Wuhan-similar variants (Wuhan, alpha, and delta), 62.50% (95% CI, 40.59 to 81.20%), in comparison to samples mostly containing Wuhan-distant variants (Omicron) 30.00% (6.67–65.25%). The developed product has relatively high diagnostic sensitivity in relation to its analytical sensitivity due to the usage of polyclonal antibodies from two species, providing a wide repertoire of antibodies against multiple N protein epitopes. Moreover, the fast, simple, and inexpensive production of polyclonal antibodies, as the most expensive assay components, would result in affordable antigen tests. [ABSTRACT FROM AUTHOR]

The emergence of the Omicron (B.1.1.529) variant of SARS-CoV-2 has precipitated a new global wave of the COVID-19 pandemic. The rapid identification of SARS-CoV-2 infection is imperative for the effective mitigation of transmission. Diagnostic modalities such as rapid antigen testing and real-time reverse transcription polymerase chain reaction (RT-PCR) offer expedient turnaround times of 10–15 min and straightforward implementation. This preliminary study assessed the correlation between outcomes of commercially available rapid antigen tests for home use and conventional reverse transcription polymerase chain reaction (RT-PCR) assays using a limited set of clinical specimens. Patients aged 5–99 years presenting to the emergency department for SARS-CoV-2 testing were eligible for enrollment (n = 5652). Direct PCR and conventional RT-PCR were utilized for the detection of SARS-CoV-2. The entire cohort of 5652 clinical specimens was assessed by both modalities to determine the clinical utility of the direct RT-PCR assay. Timely confirmation of SARS-CoV-2 infection may attenuate viral propagation and guide therapeutic interventions. Additionally, direct RT-PCR as a secondary confirmatory test for at-home rapid antigen test results demonstrated sensitivity comparable to conventional RT-PCR, indicating utility for implementation in laboratories globally, especially in resource-limited settings with constraints on reagents, equipment, and skilled personnel. In summary, direct RT-PCR enables the detection of SARS-CoV-2 with a sensitivity approaching that of conventional RT-PCR while offering expedient throughput and shorter turnaround times. Moreover, direct RT-PCR provides an open-source option for diagnostic laboratories worldwide, particularly in low- and middle-income countries. [ABSTRACT FROM AUTHOR]

Introduction: Immunosuppression after chemotherapy, stem cell transplantation or solid organ transplantation are the main risk factors for invasive fungal infections in Austria. Here, we aim to describe the status of laboratory mycology and the access to antifungal treatment in Austria. Methods: Between October and November 2021, hospitals were contacted to participate in our online survey: www.clinicalsurveys.net/uc/IFI%5fmanagement%5fcapacity/. Centres were required to provide information on their institutional profile; self‐assessment of burden of invasive fungal infections; access to microscopy, culture, serology, antigen detection and molecular testing; and availability of antifungal agents and therapeutic drug monitoring. Results: Responses were collected from university hospitals and laboratories in Graz, Innsbruck, Linz and Vienna. The four hospitals can provide tertiary care and were highly specialised, including management of patients with severe immunosuppression. All sites consider the incidence of invasive fungal infections to be moderate. Access to microscopy, culture, serology, antigen detection and molecular testing is provided regardless of laboratory. The maximum capacity to identify fungi varies from institution to institution. All currently marketed antifungal agents are available at the four sites. Conclusion: Austria is currently well equipped to deal with the emerging threat of invasive fungal infections. However, hospitals may consider preparing for the potential endemicity of certain infections in the near future. [ABSTRACT FROM AUTHOR]

Faced with the pandemic viral circulation of SARS-CoV-2, healthcare establishments have had to maintain an effective screening strategy in order to prevent nosocomial clusters. Automated antigenic tests appear to be a reliable and complementary alternative to RT-PCR (reverse transcriptase polymerase chain reaction) in order to optimize patient care in the emergency department. We report our experience of the deployment of the LumiraDx antigen tests on the LumiraDx platform, as well as the comparison of these tests' results with the RT-PCR results on a population of patients sampled in the emergency department. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the clinical performance of a combined SARS-CoV-2/influenza rapid antigen test (SIRAT) and to evaluate a SIRAT-based hospital isolation policy awaiting RT-PCR results for patients presenting at the emergency department (ED). We performed a prospective observational study including all adult patients presenting with influenza-like symptoms at the ED of two hospitals from 31 October 2022 to 31 March 2023. A SIRAT and SARS-CoV-2 and influenza RT-PCR were performed on upper respiratory samples. SIRAT results were compared with RT-PCR. Droplet and contact isolation measures (DCIM) were imposed based on SIRAT results awaiting RT-PCR. We monitored symptomatic nosocomial SARS-CoV-2 and influenza infections potentially caused by delayed isolation of patients with false negative SIRAT and the hours of unnecessary DCIM saved. We included 1740 patients of whom 1296 were hospitalized. SARS-CoV-2 and influenza A/B prevalence were 12.7% (221/1740) and 9.9% (171/1740). Sensitivity and specificity of the SIRAT were 67.7% (95% CI 61.1–73.9%) (149/220) and 99.4% (95% CI 99.0–99.8%) (1510/1518) for SARS-CoV-2 and 52.7% (95% CI 44.9–60.4%) (89/169) and 99.1% (95% CI 98.5–99.5%) (1530/1544) for influenza A/B. We found a 0% nosocomial transmission risk for SARS-CoV-2 (95% CI 0–8.8%) and influenza (95% CI 0–10%). In all, 8712 hours in total or a median up to 6 hours 59 minutes (IQR (interquartile range) 11h03) per patient of unnecessary DCIM were saved. : A SIRAT-guided hospital isolation policy awaiting RT-PCR results for patients who present at the ED can save unnecessary isolation hours without having to lead to significant symptomatic nosocomial transmission of SARS-CoV-2 or influenza viruses. [ABSTRACT FROM AUTHOR]

BackgroundThis study is the extension of the COVAG study. We compared two RATs, the Panbio COVID-19 Ag Rapid Test (Abbott) and the SD Biosensor Q SARS-CoV-2 Rapid Antigen Test (Roche), against RT-PCR on the foil of new variants.MethodsWe included 888 all-comers at a diagnostic center between October 20, 2021, and March 18, 2022. RT-PCR-positive samples with a Ct value ≤32 were examined for SARS-CoV-2 variants.FindingsThe sensitivity of the Abbott-RAT and Roche-RAT were 65 and 67%, respectively. For both RATs, lower Ct values were significantly correlated with higher sensitivity. For samples with Ct values ≤25, the sensitivities of the Roche-RAT and of the Abbott-RAT were 96 and 95%, for Ct values 25–30 both were 19%, and for Ct values ≥30 they were 6 and 2%, respectively. The RATs had substantially higher sensitivities in symptomatic than asymptomatic participants (76, 77%, vs. 29, 31%, for Abbott-RAT, Roche-RAT, respectively) and in participants referred to testing by their primary care physician (84, 85%) compared to participants who sought testing due to referral by the health department (55, 58%) or a warning by the Corona-Warn-App (49, 49%). In persons with self-reported previous COVID-19 sensitivities were markedly lower than in patients without previous COVID-19: 27% vs. 75% for Roche-RAT and 27% vs. 73% for Abbott-RAT. We did not find significant correlation between vaccination status and sensitivity. The Omicron variant was detected with a sensitivity of 94 and 92%, the delta variant with a sensitivity of 80 and 80% for Abbott-RAT and Roche-RAT, respectively. This difference is attributable to the lower Ct values of the Omicron samples compared to the Delta samples. When adjusted for the Ct value, a multivariate logistic regression did not show a significant difference between Omicron and Delta. In terms of sensitivity, we found no significant difference between the wild-type and the Omicron and Delta variants, but a significantly lower sensitivity to the alpha variant compared to the other variants.The specificities were > 99% overall.

Background: Many rapid antigen kits for SARS-CoV-2 detection have been developed and the results interpreted usually within 30 minutes. Antigen tests are recommended to be used in areas where access to the PCR method is limited, as is the case in Burkina Faso. The aim of this study is to assess the performance of "Standard TM Q COVID-19 Ag Test " in the detection of SARS-CoV-2 antigen. Methods: The evaluation was performed using swabs samples collected between January 26 and March 31, 2021, from 201 subjects previously diagnosed by RT-PCR. The performance of the rapid test “Standard TM Q COVID-19 Ag Test was compared to the RT-PCR test “STANDARD M nCoV real-time detection kit”. Results: Of these 201 samples, 16 were positive for the COVID-19 RT-PCR, and 185 were negative. The sensitivity of the "Standard TM Q COVID-19 Ag Test" was 100% (IC95%: 34.24- 100) in symptomatic subjects with a symptom onset time of 1 to 5 days. This sensitivity decreased to 66.67% (IC95%: 20.77- 93.85) in symptomatic subjects with a symptom onset time of 1 to 7 days. The specificity, it was 95% (IC95%: 83.5-98.62) in all symptomatic subjects and 93.75% (IC95%: 79.85-98.2) in subjects whose symptoms appeared between 1 and 5 days. Conclusion: The " Standard TM Q COVID-19 Ag Test " was better in subjects with delayed symptoms up to 5 days. However, this kit was not suitable for COVID-19 detection in asymptomatic subjects.

The enduringsevere acute respiratory syndrome corona virus 2 (SARS-CoV-2) global health has led to a huge market to design affordable point-of-care (PoC) examination tools and skilled laboratory procedures for its recognition. Most of the available tests for early discovery of SARS-CoV-2 nucleic acids are built on the reverse transcription polymerase chain reaction (RT-PCR); however, isothermal nucleic acid amplification tests, comprising amplification based on transcription and clustered regularly interspaced short palindromic repeats (CRISPR)-based methods, may act as favourable substitutes to the RT-PCR ideal assay. RT-PCR is an appropriate quantitative assay which requires skilled labour, sophisticated instrumentation, but time consuming. Therefore, cannot be deployed immediately in distant and asset-limited areas. A few more serological tests like rapid antigen tests, enzyme-linked immunosorbent assay (ELISA) in addition lateral flow immunoassay (LFIA), may as well be helpful in certain large sample settings however each have their own technical limitations. Thus, taking view of the present scenario; for fast, subtle, highly accurate and cost-effective detection of Covid-19, progressive nano-based biosensors can be alternative tools to control of this pandemic of the upcoming one also. In this comprehensive review, we have presented a wide investigational description of currently available covid-19 diagnostics assays, with a detailed idea about nano-biosensors-based detection approaches. This review paper also highlighted the assets and liabilities of prevailing technologies as well as approaches to further optimising the rapid and efficient diagnostics of Covid-19.

We evaluated the performance of rapid antigen (RAg) and antibody (RAb) microfluidic diagnostics with serial sampling of 71 participants at 6 visits over 2 months following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Rapid tests showed strong agreement with laboratory references (κAg = 81.0%; κAb = 87.8%). RAg showed substantial concordance to both virus growth in culture and PCR positivity 0–5 days since symptom onset (κAg-culture = 60.1% and κAg-PCR = 87.1%). PCR concordance to virus growth in culture was similar (κPCR-culture = 70.0%), although agreement between RAg and culture was better overall (κAg-culture = 45.5% vs κPCR-culture = 10.0%). Rapid antigen and antibody testing by microfluidic immunofluorescence platform are highly accurate for characterization of acute infection. [ABSTRACT FROM AUTHOR]

Objectives: Neisseria meningitidis is one of the major pathogens of meningitis in children worldwide and causes invasive meningococcal disease (IMD), which is a critical illness that mainly presents as meningitis and/or septicemia in children. Identification of N. meningitidis in cerebrospinal fluid (CSF) is the gold standard for the diagnosis of meningococcal meningitis, but antigen tests have advantages such as timely results, relatively low cost, and convenience. Yet, the diagnostic accuracy of antigen tests remains uncertain. Therefore, the aim of this meta‐analysis was to evaluate the diagnostic accuracy of antigen tests for N. meningitidis in CSF. Methods: We searched the PubMed, Embase, and Cochrane Library databases for studies evaluating the diagnostic accuracy of antigen tests for N. meningitidis in CSF. We included studies that provided sufficient data to construct a 2 × 2 table on a per‐sample basis. To determine the overall sensitivity and specificity of the antigen tests, we used polymerase chain reaction (PCR) as the reference standard and employed the hierarchical summary receiver operating characteristic model. Results: Nine studies with 4533 CSF samples were included. The meta‐analysis yielded a pooled sensitivity of 91.2% (95% confidence interval [CI]: 80.0%–100.0%) and a pooled specificity of 93.8% (95% CI: 83.9%–100.0%). A subgroup analysis of 2 studies that reported the outcomes of MeningoSpeed yielded a pooled sensitivity of 93.4% (95% CI: 90.0%–95.8%) and a pooled specificity of 91.9% (95% CI: 88.6%–94.4%). Antigen testing for the N. meningitidis serogroup X had a pooled sensitivity of 92.4% (95% CI: 85.2%–96.2%) and a pooled specificity of 99.2% (95% CI: 78.7%–100.0%). Conclusions: The studied antigen tests had high sensitivity and specificity for the diagnosis of meningococcal meningitis in CSF specimens. Antigen testing could serve as an accurate diagnostic method for assessing patients who have a suspected N. meningitidis infection. [ABSTRACT FROM AUTHOR]

SARS-CoV-2 nucleocapsid protein (NP) is the main target for COVID-19-diagnostic PCR and antigen rapid diagnostic tests (Ag-RDTs). Ag-RDTs are more convenient than PCR tests for point-of-care testing or self-testing to identify the SARS-CoV-2 antigen. The sensitivity and specificity of this method depends mainly on the affinity and specificity of NP-binding antibodies; therefore, antigen-antibody binding is key elements for the Ag-RDTs. Here, we applied the high-throughput antibody isolation platform that has been utilized to isolate therapeutic antibodies against rare epitopes. Two NP antibodies were identified to recognize non-overlapping epitopes with high affinity. One antibody specifically binds to SARS-CoV-2 NP, and the other rapidly and tightly binds to SARS-CoV-2 NP with cross-reactivity to SARS-CoV NP. Furthermore, these antibodies were compatible with a sandwich enzyme-linked immunosorbent assay that exhibited enhanced sensitivity for NP detection compared to the previously isolated NP antibodies. Thus, the NP antibody pair is applicable to more sensitive and specific Ag-RDTs, highlighting the utility of a high-throughput antibody isolation platform for diagnostics development. • Antigen-rapid diagnostic tests (Ag-RDTs) are effective in screening for COVID-19 infection especially fast point-of-care diagnostics. • A high-throughput antibody isolation platform was applied to develop new antibody pair against SARS-CoV-2 nucleocapsid protein. • The utility of the antibody pair allowed us to detect virus protein with high sensitivity and specificity. [ABSTRACT FROM AUTHOR]

Abstract Background The Omicron variant of SARS-CoV-2 led to a steep rise in transmissions, and emerging variants continue to influence case rates across the US. As public tolerance for isolation abated, CDC guidance on duration of at-home isolation of COVID-19 cases was shortened to five days if no symptoms, with no laboratory test requirement, despite more cautious approaches advocated by other federal experts. Methods We conducted a decision tree analysis of alternative protocols for ending COVID-19 isolation, estimating net costs (direct and productivity), secondary infections, and incremental cost-effectiveness ratios. Sensitivity analyses assessed the impact of input uncertainty. Results Per 100 individuals, five-day isolation had 23 predicted secondary infections and a net cost of $33,000. Symptom check on day five (CDC guidance) yielded a 23% decrease in secondary infections (to 17.8), with a net cost of $45,000. Antigen testing on day six yielded 2.9 secondary infections and $63,000 in net costs. This protocol, compared to the next best protocol of antigen testing on day five of a maximum eight-day isolation, cost an additional $1,300 per secondary infection averted. Antigen or polymerase chain reaction testing on day five were dominated (more expensive and less effective) versus antigen testing on day six. Results were qualitatively robust to uncertainty in key inputs. Conclusions A six-day isolation with antigen testing to confirm the absence of contagious virus appears the most effective and cost-effective de-isolation protocol to shorten at-home isolation of individuals with COVID-19.

Introduction: Real-time reverse transcription-polymerase chain reaction (RT-PCR) is the gold standard method for the diagnosis of Severe acute respiratory syndrome-Coronavirus-2 (SARS-CoV-2) infection. However, real-time RT-PCR is time-consuming, expensive, and requires special laboratory conditions and experienced personnel. Thus, the diagnostic importance of faster and easier-to-perform antigen-detecting rapid diagnostic tests (Ag-RDTs) has increased. With on-site application and fast turnaround time, Ag-RDTs provide quick isolation, minimizing the risk of transmission. We aimed to compare the results of the Mö-Screen Corona Antigen Test (MöLab, Langenfeld, Germany) and real-time RT-PCR. Materials and Methods: Nasopharyngeal swabs from 863 patients from January 2022 to March 2022 were included in the study. The SARS-CoV-2 antigen was assessed for using the Mö-Screen Corona Antigen Test. The SARS-CoV-2 real-time RT-PCR results were obtained within two days in 417 patients. Results: The agreeability of the real-time RT-PCR and Ag-RDT results was 96.2%. The sensitivity and specificity of Ag-RDT were 84.8% and 100%, respectively. The test sensitivity increased to 92% in specimens with Ct value

Canine parvovirus (CPV) is an acute and highly infectious virus causing disease in puppies and, thus, affecting the global dog industry. The current CPV detection methods are limited by their sensitivity and specificity. Hence, the current study sought to develop a rapid, sensitive, simple, and accurate immunochromatographic (ICS) test to detect and control the spread and prevalence of CPV infection. More specifically, 6A8, a monoclonal antibody (mAb) with high specificity and sensitivity, was obtained by preliminary screening. The 6A8 antibody was labelled with colloidal gold particles. Subsequently, 6A8 and goat anti-mouse antibodies were coated onto a nitrocellulose membrane (NC) as the test and control lines, respectively. Furthermore, 6A8 and rabbit IgG antibodies were labelled with fluorescent microspheres and evenly sprayed onto a glass fibre membrane. Both strips could be prepared in 15 min with no noticeable cross-reactivity with other common canine intestinal pathogens. The strips were simultaneously used to detect CPV in 60 clinical samples using real-time quantitative PCR, hemagglutination, and hemagglutination inhibition assays. The colloidal gold (fluorescent) ICS test strip was stable for 6 (7) and 4 (5) months at 4 °C and room temperature (18–25 °C). Both test strips were easy to prepare and rapidly detected CPV with high sensitivity and specificity. Moreover, the results were easily interpretable. This study establishes a simple method for two CPV diseases, colloidal gold and fluorescent immunochromatographic (ICS) test strips. Key points: • CPV test strips do not exhibit cross-reactivity with other canine intestinal pathogens. • The strips are stable for months at 4 °C and at room temperature (18–25 °C). • These strips are a promising approach for the timely diagnosis and treatment of CPV. [ABSTRACT FROM AUTHOR]

Background: Many rapid antigen kits for SARS-CoV-2 detection have been developed and the results interpreted usually within 30 minutes. Antigen tests are recommended to be used in areas where access to the PCR method is limited, as is the case in Burkina Faso. The aim of this study is to assess the performance of "Standard™ Q COVID-19 Ag Test" in the detection of SARS-CoV-2 antigen. Methods: The evaluation was performed using swabs samples collected between January 26 and March 31, 2021, from 201 subjects previously diagnosed by RT-PCR. The performance of the rapid test "Standard™ Q COVID-19 Ag Test was compared to the RT-PCR test "STANDARD M nCoV real-time detection kit". Results: Of these 201 samples, 16 were positive for the COVID-19 RTPCR, and 185 were negative. The sensitivity of the "Standard™ Q COVID-19 Ag Test" was 100% (IC95%: 34.24-100) in symptomatic subjects with a symptom onset time of 1 to 5 days. This sensitivity decreased to 66.67% (IC95%: 20.77-93.85) in symptomatic subjects with a symptom onset time of 1 to 7 days. The specificity, it was 95% (IC95%: 83.5-98.62) in all symptomatic subjects and 93.75% (IC95%: 79.85-98.2) in subjects whose symptoms appeared between 1 and 5 days. Conclusion: The "Standard™ Q COVID-19 Ag Test" was better in subjects with delayed symptoms up to 5 days. However, this kit was not suitable for COVID-19 detection in asymptomatic subjects. [ABSTRACT FROM AUTHOR]

Background: The COVID-19 pandemic is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Rapid identification and isolation of patients with COVID-19 are critical strategies to contain COVID-19. The saliva antigen test has the advantages of noninvasiveness and decreased transmission risk to health-care professionals. This meta-analysis investigated the diagnostic accuracy of the saliva antigen test for SARS-CoV-2. Methods: We searched for relevant studies in PubMed, Embase, Cochrane Library, and Biomed Central. Studies evaluating the diagnostic accuracy of saliva antigen tests for SARS-CoV-2 were included. The data of the included studies were used to construct a 2 × 2 table on a per patient basis. The overall sensitivity and specificity of saliva antigen tests were determined using a bivariate random-effects model. Results: Nine studies enrolling 9842 patients were included. The meta-analysis generated a pooled sensitivity of 65.3% and a pooled specificity of 99.7%. A subgroup analysis of the studies performing the chemiluminescent enzyme immunoassay (CLEIA) for participants from airports and public health centers revealed a pooled sensitivity of 93.6%. Conclusion: Our findings demonstrated that the saliva antigen test performed using CLEIA exhibited higher sensitivity for the detection of SARS-CoV-2. Therefore, the saliva antigen test performed using CLEIA might be an effective and noninvasive screening tool for SARS-CoV-2.

Background Expansion of the testing capacities for severe acute respiratory syndrome-coronavirus-2 is an important issue in the face of ever-increasing case load. So, there is need of point-of-care diagnostic tests in the existing laboratory capacities for early treatment, isolation, and clinical decision making, especially in resource limited settings. Materials and Methods This prospective cohort study was conducted at Jai Prakash Narayan Apex Trauma Center, All India Institute of Medical Sciences, New Delhi. Nasopharyngeal samples and blood samples were collected for antigen and antibody testing. Rapid antigen test was performed as per the kit's instructions. The performance of the kit was compared with the gold standard reverse transcription polymerase chain reaction (RT-PCR) testing. Results Eighty-eight out of 110 patients tested positive by RT-PCR for coronavirus disease 2019 in last 48 to 72 hours were included in the study. Overall, the sensitivity of combined antibody test was 52%, antigen test 26%, and combined sensitivity of both antigen and antibody was 72.7%, respectively. Conclusion The combo kit needs to be used with caution in low prevalence settings, where cases may be missed.

Abstract Background The diagnostic accuracy of unsupervised self-testing with rapid antigen diagnostic tests (Ag-RDTs) is mostly unknown. We studied the diagnostic accuracy of a self-performed SARS-CoV-2 saliva and nasal Ag-RDT in the general population. Methods This large cross-sectional study consecutively included unselected individuals aged $$\ge$$ ≥ 16 years presenting for SARS-CoV-2 testing at three public health service test sites. Participants underwent molecular test sampling and received two self-tests (the Hangzhou AllTest Biotech saliva self-test and the SD Biosensor nasal self-test by Roche Diagnostics) to perform themselves at home. Diagnostic accuracy of both self-tests was assessed with molecular testing as reference. Results Out of 2819 participants, 6.5% had a positive molecular test. Overall sensitivities were 46.7% (39.3–54.2%) for the saliva Ag-RDT and 68.9% (61.6–75.6%) for the nasal Ag-RDT. With a viral load cut-off (≥ 5.2 log10 SARS-CoV-2 E-gene copies/mL) as a proxy of infectiousness, these sensitivities increased to 54.9% (46.4–63.3%) and 83.9% (76.9–89.5%), respectively. For the nasal Ag-RDT, sensitivities were 78.5% (71.1–84.8%) and 22.6% (9.6–41.1%) in those symptomatic and asymptomatic at the time of sampling, which increased to 90.4% (83.8–94.9%) and 38.9% (17.3–64.3%) after applying the viral load cut-off. In those with and without prior SARS-CoV-2 infection, sensitivities were 36.8% (16.3–61.6%) and 72.7% (65.1–79.4%). Specificities were > 99% and > 99%, positive predictive values > 70% and > 90%, and negative predictive values > 95% and > 95%, for the saliva and nasal Ag-RDT, respectively, in most analyses. Most participants considered the self-performing and result interpretation (very) easy for both self-tests. Conclusions The Hangzhou AllTest Biotech saliva self Ag-RDT is not reliable for SARS-CoV-2 detection, overall, and in all studied subgroups. The SD Biosensor nasal self Ag-RDT had high sensitivity in individuals with symptoms and in those without prior SARS-CoV-2 infection but low sensitivity in asymptomatic individuals and those with a prior SARS-CoV-2 infection which warrants further investigation.

The Nucleocapsid (N) protein is highlighted as the main target for COVID-19 diagnosis by antigen detection due to its abundance in circulation early during infection. However, the effects of the described mutations in the N protein epitopes and the efficacy of antigen testing across SARS-CoV-2 variants remain controversial and poorly understood. Here, we used immunoinformatics to identify five epitopes in the SARS-CoV-2 N protein (N(34–48), N(89–104), N(185–197), N(277–287), and N(378–390)) and validate their reactivity against samples from COVID-19 convalescent patients. All identified epitopes are fully conserved in the main SARS-CoV-2 variants and highly conserved with SARS-CoV. Moreover, the epitopes N(185–197) and N(277–287) are highly conserved with MERS-CoV, while the epitopes N(34–48), N(89–104), N(277–287), and N(378–390) are lowly conserved with common cold coronaviruses (229E, NL63, OC43, HKU1). These data are in accordance with the observed conservation of amino acids recognized by the antibodies 7R98, 7N0R, and 7CR5, which are conserved in the SARS-CoV-2 variants, SARS-CoV and MERS-CoV but lowly conserved in common cold coronaviruses. Therefore, we support the antigen tests as a scalable solution for the population-level diagnosis of SARS-CoV-2, but we highlight the need to verify the cross-reactivity of these tests against the common cold coronaviruses. [ABSTRACT FROM AUTHOR]

This prospective study aimed to evaluate the performance of the InstaView COVID-19 (coronavirus diseases 2019) Antigen Home Test (InstaView AHT) which detects severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigens. In this test kit, surface-enhanced Raman spectroscopy was used, a stacking pad was inserted, and nasal swab and salivary swab samples were used simultaneously to improve performance. The clinical performance of the InstaView AHT was compared to that of RT-PCR using nasopharyngeal samples. The participants without any prior training were recruited and performed the sample collection, testing, and interpretation of the results by themselves. Of the 91 PCR-positive patients, 85 had positive InstaView AHT results. The sensitivity and specificity of the InstaView AHT were 93.4% (95% confidence interval [CI]: 86.2–97.5) and 99.4% (95% CI: 98.2–99.9). The sensitivity of the InstaView AHT was above 90% for all samples obtained from patients with Ct ≤ 20, 20 < Ct ≤ 25, and 25 < Ct ≤ 30 (100%, 95.1%, and 92.0%, respectively). The InstaView AHT can be used as an alternative to RT-PCR testing because of its relatively high sensitivity and specificity, especially when SARS-CoV-2 prevalence is high, and the availability of RT-PCR testing is limited. [ABSTRACT FROM AUTHOR]

Point-of-care antigen tests are an important tool for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detection, yet are less clinically sensitive than real-time reverse-transcription polymerase chain reaction (RT-PCR), affecting their efficacy as screening procedures. Our goal in this analysis was to see whether we could improve this sensitivity by considering antigen test results in combination with other relevant information, namely exposure status and reported symptoms. In November 2020, we collected 3,419 paired upper respiratory specimens tested by RT-PCR and the Abbott BinaxNOW (Abbott Laboratories, Abbott Park, Illinois) antigen test at 2 community testing sites in Pima County, Arizona. We used symptom, exposure, and antigen-testing data to evaluate the sensitivity and specificity of various symptom definitions in predicting RT-PCR positivity. Our analysis yielded 6 novel multisymptom case definitions with and without antigen test results, the best of which overall achieved a Youden's J index of 0.66, as compared with 0.53 for antigen testing alone. Using a random forest as a guide, we show that this definition, along with our others, does not lose the ability to generalize well to new data despite achieving optimal performance in our sample. Our methodology is broadly applicable, and our code is publicly available to aid public health practitioners in developing or fine-tuning their own case definitions. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic took place during the years 2020–2022 and the virus, named SARS-CoV-2, seems likely to have resulted in an endemic disease. Nevertheless, widespread COVID-19 has given rise to several major molecular diagnostics' facts and concerns that have emerged during the overall management of this disease and the subsequent pandemic. These concerns and lessons are undeniably critical for the prevention and control of future infectious agents. Furthermore, most populaces were introduced to several new public health maintenance strategies, and again, some critical events arose. The purpose of this perspective is to thoroughly analyze all these issues and the concerns, such as the molecular diagnostics' terminologies, their role, as well as the quantity and quality issues with a molecular diagnostics' test result. Furthermore, it is speculated that society will be more vulnerable in the future and prone to emerging infectious diseases; thus, a novel preventive medicine's plan for the prevention and control of future (re)emerging infectious diseases is presented, so as to aid the early prevention of future epidemics and pandemics. [ABSTRACT FROM AUTHOR]

The emergence of the Omicron (B.1.1.529) variant of SARS-CoV-2 has precipitated a new global wave of the COVID-19 pandemic. The rapid identification of SARS-CoV-2 infection is imperative for the effective mitigation of transmission. Diagnostic modalities such as rapid antigen testing and real-time reverse transcription polymerase chain reaction (RT-PCR) offer expedient turnaround times of 10–15 min and straightforward implementation. This preliminary study assessed the correlation between outcomes of commercially available rapid antigen tests for home use and conventional reverse transcription polymerase chain reaction (RT-PCR) assays using a limited set of clinical specimens. Patients aged 5–99 years presenting to the emergency department for SARS-CoV-2 testing were eligible for enrollment (n = 5652). Direct PCR and conventional RT-PCR were utilized for the detection of SARS-CoV-2. The entire cohort of 5652 clinical specimens was assessed by both modalities to determine the clinical utility of the direct RT-PCR assay. Timely confirmation of SARS-CoV-2 infection may attenuate viral propagation and guide therapeutic interventions. Additionally, direct RT-PCR as a secondary confirmatory test for at-home rapid antigen test results demonstrated sensitivity comparable to conventional RT-PCR, indicating utility for implementation in laboratories globally, especially in resource-limited settings with constraints on reagents, equipment, and skilled personnel. In summary, direct RT-PCR enables the detection of SARS-CoV-2 with a sensitivity approaching that of conventional RT-PCR while offering expedient throughput and shorter turnaround times. Moreover, direct RT-PCR provides an open-source option for diagnostic laboratories worldwide, particularly in low- and middle-income countries.

In this study, a cost-effective sandwich ELISA test, based on polyclonal antibodies, for routine quantification SARS-CoV-2 nucleocapsid (N) protein was developed. The recombinant N protein was produced and used for the production of mice and rabbit antisera. Polyclonal N protein-specific antibodies served as capture and detection antibodies. The prototype ELISA has LOD 0.93 ng/mL and LOQ 5.3 ng/mL, with a linear range of 1.52–48.83 ng/mL. N protein heat pretreatment (56 °C, 1 h) decreased, while pretreatment with 1% Triton X-100 increased analytical ELISA sensitivity. The diagnostic specificity of ELISA was 100% (95% CI, 91.19–100.00%) and sensitivity was 52.94% (95% CI, 35.13–70.22%) compared to rtRT-PCR (Ct < 40). Profoundly higher sensitivity was obtained using patient samples mostly containing Wuhan-similar variants (Wuhan, alpha, and delta), 62.50% (95% CI, 40.59 to 81.20%), in comparison to samples mostly containing Wuhan-distant variants (Omicron) 30.00% (6.67–65.25%). The developed product has relatively high diagnostic sensitivity in relation to its analytical sensitivity due to the usage of polyclonal antibodies from two species, providing a wide repertoire of antibodies against multiple N protein epitopes. Moreover, the fast, simple, and inexpensive production of polyclonal antibodies, as the most expensive assay components, would result in affordable antigen tests.

Zelalem Desalegn,1,&ast; Shemse Sebre,1,&ast; Meron Yohannes,2 Aminu Seman,1 Welelta Shiferaw,3 Muluneh Ademe,1 Habtamu Biazin,1 Ededia Firdawoke,1 Yehenew Asemamaw,1 Brhanu Teka,1 Seifegebriel Teshome,1 Wondwossen Amogne,4 Adamu Addissie,5,6 Yirgu Gebrehiwot,7 Eva Kantelhardt,6 Tamrat Abebe1 1Department of Microbiology, Immunology and Parasitology, School of Medicine, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia; 2Department of Medical Laboratory Sciences, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia; 3Department of Psychiatry, School of Medicine, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia; 4Department of Internal Medicine, College of Health Sciences, School of Medicine, Addis Ababa University, Addis Ababa, Ethiopia; 5School of Public Health, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia; 6Institute of Medical Epidemiology, Biostatistics and Informatics, Martin-Luther-University, Halle, Germany; 7Department of Obstetrics and Gynecology, College of Health Sciences, School of Medicine, Addis Ababa University, Addis Ababa, Ethiopia&ast;These authors contributed equally to this workCorrespondence: Zelalem Desalegn, Department of Microbiology, Immunology and Parasitology, College of Health Sciences, Addis Ababa University, P.O. Box: 9086, Addis Ababa, Ethiopia, Email zelalem.desalegn@aau.edu.et; tzollove@gmail.comBackground: When faced with a public health problem such as the COVID-19 pandemic, devising a test with an accurate and rapid diagnostic capacity is critical to contain the disease. We compared the diagnostic performance of a rapid antigen test in comparison with a reference method, namely a real-time polymerase chain reaction (RT-PCR) assay.Methods: We enrolled patients with confirmed COVID-19 from two selected hospital in Addis Ababa, Ethiopia, between January and November 2021. We assessed the performance of the Standard Q COVID-19 Ag Kit (SD Biosensor, Republic of Korea) in 200 nasopharyngeal and nasal swab samples.Results: Out of the 200 samples utilized for the diagnostic performance evaluation, equal proportion of the samples were confirmed positive and negative for SARS-CoV-2 based on RT-PCR. Of the 100 confirmed positive cases, 95 showed positive results with the rapid antigen test, yielding a sensitivity of 95% (95% confidence interval [CI] 88.7– 98.4%). Of the 100 confirmed negative cases, there were three false-positive results, yielding a specificity of 97% (95% CI 91.5– 99.4%). The sensitivity of the rapid antigen test was higher for samples with an RT-PCR cycle threshold (Ct) value ≤ 25 compared with samples with a higher Ct value.Conclusion: The finding demonstrated that the detection capacity of the Standard Q COVID-19 Ag Test meets the requirements set by the Ministry of Health Ethiopia. The high sensitivity and specificity of the test device indicate the possibility of using it for diagnostic and clinical purposes in resource-constrained settings such as Ethiopia.Keywords: SARS-CoV-2, COVID-19, antigen test

Abstract Background RSV-incidence estimates obtained from routinely-collected healthcare data (e.g., MarketScan) are commonly adjusted for under-reporting using test positivity reported in national Surveillance Systems (NREVSS). However, NREVSS lacks detail on patient-level characteristics and the validity of applying a single positivity estimate across diverse patient groups is uncertain. We aimed to describe testing practices and test positivity across subgroups of private health insurance enrollees in the US and illustrate the possible magnitude of misclassification when using NREVSS to correct for RSV under ascertainment. Methods Using billing records, we determined distributions of RSV-test claims and test positivity among a national sample of private insurance enrollees. Tests were considered positive if they coincided with an RSV-diagnosis. We illustrated the influence of positivity variation across sub-populations when accounting for untested acute respiratory infections. Results Most tests were for children (age 0–4: 65.8%) and outpatient encounters (78.3%). Test positivity varied across age (0–4: 19.8%, 5–17: 1.8%, adults: 0.7%), regions (7.6–16.1%), settings (inpatient 4.7%, outpatient 14.2%), and test indication (5.0–35.9%). When compared to age, setting or indication-specific positivity, bias due to using NREVSS positivity to correct for untested ARIs ranged from − 76% to 3556%. Conclusions RSV-test positivity depends on the characteristics of patients for whom those tests were ordered. NREVSS-based correction for RSV-under-ascertainment underestimates the true incidence among children and overestimate rates among adults. Demographic-specific detail on testing practice and positivity can improve the accuracy of RSV-incidence estimates.

ABSTRACT Background: SARS-CoV-2 virus originated in Wuhan (China) in December (2019) and quickly spread worldwide. Antigen tests are rapid diagnostic tests (RDT) that produce results in 15-30 min and are an important tool for the scale-up of COVID-19 testing. COVID-19 diagnostic tests are authorized for self-testing at home in some countries, including Brazil. Widespread COVID-19 diagnostic testing is required to guide public health policies and control the speed of transmission and economic recovery. Methods: Patients with suspected COVID-19 were recruited at the Hospital da Baleia (Belo Horizonte, Brazil). The SARS-CoV-2 antigen-detecting rapid diagnostic tests were evaluated from June 2020 to June 2021 using saliva, nasal, and nasopharyngeal swab samples from 609 patients. Patient samples were simultaneously tested using a molecular assay (RT-qPCR). Sensitivity, specificity, accuracy, and positive and negative predictive values were determined using the statistical program, MedCalc, and GraphPad Prism 8.0. Results: The antigen-detecting rapid diagnostic tests displayed 98% specificity, 60% sensitivity, 96% positive predictive value, and moderate concordance with RT-qPCR. Substantial agreement was found between the two methods for patients tested < 7 days of symptom onset. Conclusions: Our findings support the use of Ag-RDT as a valuable and safe diagnostic method. Ag-RDT was also demonstrated to be an important triage tool for suspected COVID-19 patients in emergencies. Overall, Ag-RDT is an effective strategy for reducing the spread of SARS-CoV-2 and contributing to COVID-19 control.

Objectives: Rotavirus infection is the leading cause of acute gastroenteritis (AGE) in children. Children with rotavirus infection may have symptoms such as diarrhoea or vomiting. Diarrheal diseases caused by rotavirus and other enteric pathogens cannot be differentiated on the basis of clinical symptoms. Therefore, diagnostic testing is essential to confirm a diagnosis of rotavirus infection. The aim of the meta‐analysis is to evaluate the diagnostic accuracy of immunochromatographic rotavirus antigen tests in children. Methods: We searched the PubMed, Embase, Cochrane Library and Google Scholar databases for studies evaluating the diagnostic accuracy of antigen tests for rotavirus in children. We included studies that provided sufficient data to construct a 2 × 2 table on a per patient basis. The overall sensitivity and specificity of the antigen tests were determined using a bivariate random‐effects model. Results: In total, 12 studies with 4407 participants were included in the study. The meta‐analysis yielded a pooled sensitivity of 89.2% (95% confidence interval [CI]: 77.4%–95.3%) and pooled specificity of 93.2% (95% CI: 83.8%–97.3%). A subgroup analysis of such tests in children aged ≤5 years yielded a pooled sensitivity of 87.1% and pooled specificity of 91.8%. Another subgroup analysis of high‐quality studies involving 820 participants yielded a pooled sensitivity of 92.3% and pooled specificity of 95.2%. Conclusions: Rotavirus antigen tests have high sensitivity for the diagnosis of rotavirus infection in children with AGE. In addition, such tests may be effective for the identification and clinical management of rotavirus infection in children and the prevention of disease progression. [ABSTRACT FROM AUTHOR]

Introduction: Rapid antigen tests have gained importance during the COVID-19 pandemic due to low prices and availability. The present study investigated the performance of the SARS-CoV-2 rapid diagnostic test in diagnosing patients with COVID-19 referred to the emergency department. Methods: In this diagnostic accuracy study, patients with suspected COVID-19 referred to Imam Hossein and Shohadaye Tajrish Hospitals, Tehran, Iran, were examined. All patients were subjected to a rapid corona test according to the manufacturer's guide and a chest computed tomography (CT) scan as the standard test. The screening characteristics of the rapid test compared to CT scan were calculated and reported. Results: 183 people with an average age of 46.83 ± 14.26 (range: 21-83) years entered the study. 141 suspected cases of COVID-19 (77%) had evidence of lung involvement in CT, and the rapid test was positive in 83 (45%) cases. Out of 83 patients who tested positive for COVID-19, all (100%) had positive chest CT findings. Out of the 100 patients who tested negative, 42 patients (42%) had negative chest CT findings, and 58 patients (58%) had positive CT scans. The sensitivity, specificity, and accuracy of the mentioned test were 58.86, 100.00, and 68.30 percent, respectively. Conclusion: Due to the relatively low sensitivity, the Rapid SARS-CoV-2 antigen test fails to screen for SARS-CoV-2 infection. However, it can be used to confirm the presence of the disease in symptomatic individuals and reduce virus transmission during the COVID-19 pandemic. [ABSTRACT FROM AUTHOR]

Background Expansion of the testing capacities for severe acute respiratory syndrome-coronavirus-2 is an important issue in the face of ever-increasing case load. So, there is need of point-of-care diagnostic tests in the existing laboratory capacities for early treatment, isolation, and clinical decision making, especially in resource limited settings. Materials and Methods This prospective cohort study was conducted at Jai Prakash Narayan Apex Trauma Center, All India Institute of Medical Sciences, New Delhi. Nasopharyngeal samples and blood samples were collected for antigen and antibody testing. Rapid antigen test was performed as per the kit's instructions. The performance of the kit was compared with the gold standard reverse transcription polymerase chain reaction (RT-PCR) testing. Results Eighty-eight out of 110 patients tested positive by RT-PCR for coronavirus disease 2019 in last 48 to 72 hours were included in the study. Overall, the sensitivity of combined antibody test was 52%, antigen test 26%, and combined sensitivity of both antigen and antibody was 72.7%, respectively. Conclusion The combo kit needs to be used with caution in low prevalence settings, where cases may be missed. [ABSTRACT FROM AUTHOR]

Aim: The vaccination campaign against SARS-CoV2 in Germany started at the peak of the second wave. An outbreak in an elderly care home occurred in our county at the time of the second vaccination. We describe a package of measures to control the outbreak and to prevent a spill over into the general population. Subjects and methods: After outbreak confirmation, a package of measures such as quarantine of the elderly care home, staff and visitors, and their households was implemented. By sequential testing, quarantine measures were lifted. Surveillance of staff and residents by rapid antigen test and symptom monitoring was used in parallel. Results: The outbreak was on-going for around 17 days until it was noticed by a symptomatic external staff member as index case. A total of 23 out of 96 residents (24.0%) and nine out of 114 staff (7.9%) were infected. Three residents died. Effective first-dose vaccine coverage was 85.4% in residents, 27.4% in internal, and 10.5% in external staff. Given the long latency period, the use of household quarantine prevented a spill over into the public. Already 16 days after notification of the index case the outbreak could be declared over. Conclusions: Interferences between vaccination coverage and outbreak characteristics in regard to an extended latency period were observed. Household quarantine of case as well as contact households is of increased importance in the era of vaccination to prevent further spread into the general population until population-based control measures and lockdowns can be lifted. [ABSTRACT FROM AUTHOR]

Background: International travel poses the risk of importing SARS-CoV-2 infections and introducing new viral variants into the country of destination. Established measures include mandatory quarantine with the opportunity to abbreviate it with a negative rapid antigen test (RAT). Methods: A total of 1,488 returnees were tested for SARS-CoV-2 with both PCR and RAT no earlier than 5 days after arrival. We assessed the sensitivity and specificity of the RAT. Positive samples were evaluated for infectivity in vitro in a cell culture outgrowth assay. We tracked if participants who tested negative were reported positive within 2 weeks of the initial test. Results: Potential infectiousness was determined based on symptom onset analysis, resulting in a sensitivity of the antigen test of 89% in terms of infectivity. The specificity was 100%. All positive outgrowth assays were preceded by a positive RAT, indicating that all participants with proven in vitro infectivity were correctly identified. None of the negative participants tested positive during the follow-up. Conclusions: RAT no earlier than the 5th day after arrival was a reliable method for detecting infectious travellers and can be recommended as an appropriate method for managing SARS-CoV-2 travel restrictions. Compliance to the regulations and a high standard of test quality must be ensured.

Background: One strategy for reducing spread of COVID-19 is to contain the infection with broad screening, isolating infected individuals, and tracing contacts. This strategy requires widely available, reliable SARS-CoV-2 testing. To increase testing, rapid antigen detection tests (RADTs) were developed for self-sampling, self-testing, and self-interpretation. This study examined diagnostic performance, user acceptability, and safety of nasal self-RADTs compared with polymerase chain reaction (PCR) testing. Methods: Self-RADT kits were distributed at a public COVID-19 test center in Aarhus, Denmark or delivered to participants. Participants reported test results and test preferences. During enrollment, participants reported occurrence and duration of symptoms consistent with COVID-19. Sensitivity and specificity of self-RADT, relative to oropharyngeal PCR testing, were calculated. Results: Among 827 participants, 102 showed positive PCR test results. Sensitivities of the self-RADTs were 65.7% (95% confidence interval [CI]: 49.2–79.2; DNA Diagnostic) and 62.1% (95% CI: 50.1–72.9; Hangzhou), and specificities were 100% (95% CI: 99.0–100; DNA Diagnostic) and 100% (95% CI: 98.9–100; Hangzhou). The sensitivities of both self-RADTs appeared higher in symptomatic participants than in asymptomatic participants. Two of every 3 participants preferred self-RADT over PCR test. Conclusion: Self-performed RADTs were reliable, user-acceptable, and safe among laypeople as a supplement to professionally collected oropharyngeal PCR testing.

Faced with the pandemic viral circulation of SARS-CoV-2, healthcare establishments have had to maintain an effective screening strategy in order to prevent nosocomial clusters. Automated antigenic tests appear to be a reliable and complementary alternative to RT-PCR (reverse transcriptase polymerase chain reaction) in order to optimize patient care in the emergency department. We report our experience of the deployment of the LumiraDx antigen tests on the LumiraDx platform, as well as the comparison of these tests’ results with the RT-PCR results on a population of patients sampled in the emergency department.

Background: The development of easy-to-perform diagnostic methods is highly important for detecting current coronavirus disease (COVID-19). This pilot study aimed at developing a lateral flow assay (LFA)-based test prototype to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus in saliva samples. Methods: Mice were immunized using the recombinant receptor-binding domain (rRBD) of SARS-CoV-2 virus spike protein. The combinations of the obtained mouse anti-receptor-binding domain (RBD) polyclonal antibodies (PAbs) and several commercial antibodies directed against the SARS-CoV-2 spike protein were used for enzyme-linked immunosorbent assay (ELISA) to select antibody pairs for LFA. The antibody pairs were tested in a LFA format using saliva samples from individuals with early SARS-CoV-2 infection (n = 9). The diagnostic performance of the developed LFA was evaluated using saliva samples from hospitalized COVID-19 patients (n = 111); the median time from the onset of symptoms to sample collection was 10 days (0–24 days, interquartile range (IQR): 7–13). The reverse transcription-polymerase chain reaction (rRT-PCR) was used as a reference method. Results: Based on ELISA and preliminary LFA results, a combination of mouse anti-RBD PAbs (capture antibody) and rabbit anti-spike PAbs (detection antibody) was chosen for clinical analysis of sample. When compared with rRT-PCR results, LFA exhibited 26.5% sensitivity, 58.1% specificity, 50.0% positive prediction value (PPV), 33.3% negative prediction value (NPV), and 38.7% diagnostic accuracy. However, there was a reasonable improvement in assay specificity (85.7%) and PPV (91.7%) when samples were stratified based on the sampling time. Conclusion: The developed LFA assay demonstrated a potential of SARS-CoV-2 detection in saliva samples. Further technical assay improvements should be made to enhance diagnostic performance followed by a validation study in a larger cohort of both asymptomatic and symptomatic patients in the early stage of infection.

Abstract Background Antigen tests for SARS-CoV-2 offer advantages over nucleic acid amplification tests (NAATs, such as RT-PCR), including lower cost and rapid return of results, but show reduced sensitivity. Public health organizations recommend different strategies for utilizing NAATs and antigen tests. We sought to create a framework for the quantitative comparison of these recommended strategies based on their expected performance. Methods We utilized a decision analysis approach to simulate the expected outcomes of six testing algorithms analogous to strategies recommended by public health organizations. Each algorithm was simulated 50,000 times in a population of 100,000 persons seeking testing. Primary outcomes were number of missed cases, number of false-positive diagnoses, and total test volumes. Outcome medians and 95% uncertainty ranges (URs) were reported. Results Algorithms that use NAATs to confirm all negative antigen results minimized missed cases but required high NAAT capacity: 92,200 (95% UR: 91,200-93,200) tests (in addition to 100,000 antigen tests) at 10% prevalence. Selective use of NAATs to confirm antigen results when discordant with symptom status (e.g., symptomatic persons with negative antigen results) resulted in the most efficient use of NAATs, with 25 NAATs (95% UR: 13-57) needed to detect one additional case compared to exclusive use of antigen tests. Conclusions No single SARS-CoV-2 testing algorithm is likely to be optimal across settings with different levels of prevalence and for all programmatic priorities. This analysis provides a framework for selecting setting-specific strategies to achieve acceptable balances and trade-offs between programmatic priorities and resource constraints.

Rapid antigen test has a very important value as one of tools to address the Covid pandemic. Though this test is not as accurate as polymerase chain reaction (PCR) testing. As viral antigen appears before antibody formation in infected person. It is a specific marker of virus. Therefore, for detection of this highly infectious disease at an early stage, viral antigen testing can be a useful strategy in scenario of community transmission to prevent further spread. In India an advisory was issued by ICMR (on 14th June 2020) regarding usage of RAT for quick detection of COVID-19 positive patients. During second wave, Rapid antigen testing was advised only in symptomatic individuals and immediate contacts of laboratory confirmed positive cases. Though no test is perfect when it comes to the attributes of accuracy, accessibility, affordability, and timeliness of results. However, Rapid antigen test can be used as a useful test in public health that can benefit the larger population in breaking the chain of transmission if used wisely in different settings and according to the timeline of symptoms.

Title: Evaluation of diagnostic value of SARS-CoV-2 rapid diagnostic test in patients with Covid-19 Introduction: The standard RT-PCR test is a time-consuming diagnostic test with difficult accessibility and high cost, so in order to early diagnose and prevent the spread of Covid-19 disease, access to a quick, inexpensive diagnostic test with easy access is essential. This study aimed to evaluate diagnostic value of SARS-CoV-2 rapid diagnostic test in patients with Covid-19. Materials & Methods: The present study is a cross-sectional study in type of diagnostic value that was performed on 188 patients with symptoms of Covid-19 referred to the emergency department of Imam Hossein and Shohadaye Tajrish hospitals in Tehran. In this study, SARS-CoV-2 rapid diagnostic test was performed immediately after sampling and according to the manufacturer's instructions (reading in 10 minutes). Then chest CT scan was performed less immediately after collecting samples to compare with the results of rapid antigen detection test. Data were collected and analyzed using Spss software V.26 and descriptive-mean and Chi-square statistical tests. Results: Results showed that out of 83 patients who were diagnosed with Covid-19 positively based on rapid diagnostic test, all of them (100%) were also positive based on chest CT scan results, and out of 100 patients diagnosed Covid-19 negative based on rapid diagnostic test, 42 patients (42%) were true negative and 58 were positive base of chest CT scan results. The sensitivity of the rapid diagnostic test compared to chest CT scan was 100%, its specificity was 42%, its positive predictive value was 58.86% and its negative predictive value was 100%. Conclusion: Due to the high accuracy and rapid diagnostic of rapid diagnostic test (SARS-CoV-2), this test is a valid and reliable tool for rapid diagnosis of Covid-19 disease in emergency cases.

Background: The authenticity and importance of RT-PCR testing cannot be overstated, for resource-limited settings like Bangladesh, especially in places where RT -PCR facilities are unavailable, rapid antigen testing could be an important supportive tool in SARS-CoV-2 diagnosis. Objective: The aim of this study was to compare rapid SARS-CoV-2 antigen detection test with RT-PCR for viral gene detection assay. Methodology: This cross-sectional study was performed at National Institute of Laboratory Medicine and Referral Center (NILMRC), Dhaka between March and April 2021. The nasopharyngeal swab samples were obtained from COVID-19 suspected cases collected from NILMRC virology lab. RT-PCR testing was conducted by Novel Coronavirus Nucleic Acid Diagnostic Kit. Rapid antigen testing was conducted using Standard Q COVID-19 Ag test. Results: The median age was 35.2 years. Among the confirmed cases, 63.0% were male patients. A total of 68 samples came out as positive and 226 were negative using both methods. Additionally, four more positive cases were detected by the Rapid Antigen Testing method. The sensitivity and specificity of the rapid antigen test was found to be 94.0% and 99.0% respectively. Conclusions: Rapid antigen test and rt-PCR showed almost similar sensitivity and specificity. [ABSTRACT FROM AUTHOR]