Diagnostic Accuracy of Rapid Antigen Test Kits for Detecting SARS-CoV-2: A Systematic Review and Meta-Analysis of 17,171 Suspected COVID-19 Patients

Prevalence of nephropathy among diabetic patients in North American region: A systematic review and meta-analysis

BACKGROUND

Nephropathy is one of the most common microvascular impediments of diabetes mellitus. In this study, we aimed to estimate the prevalence of nephropathy in diabetic patients across the North American region.

METHODS

Eligible studies were screened out from 3 electronic databases, for example, PubMed, Google Scholar, and ScienceDirect using specific search keywords based on the eligibility criteria. Extracting the data from the included studies publication bias, quality assessment, outlier investigation, and meta-analysis was done followed by the subgroup analysis. A total of 11 studies met the study inclusion criteria. Meta-analysis was performed with the extracted data.

RESULTS

Pooled prevalence of 28.2% (95% confidence interval [CI]: 19.7-36.7) with a high rate of heterogeneity (I2 = 100%) was identified. The pooled prevalence of nephropathy among diabetic patients in the United States of America, Canada, and Mexico was 24.2% (95% CI: 13.8-34.5), 31.2% (95% CI: 25.8-36.5), and 31.1% (95% CI: 20.8-41.5), respectively.

CONCLUSION

The prevalence of nephropathy among diabetic patients was found lower in the United States of America as compared to Canada and Mexico. Besides, the pooled prevalence of the North American region was found to be lower as compared to the African, European, and Asian regions. Minimizing the pathogenic factors, sufficient diagnostic, healthcare facilities, and awareness are recommended to improve the situation.

Use of high-resolution fluorescence in situ hybridization for fast and robust detection of SARS-CoV-2 RNAs

Early, rapid, and accurate diagnostic tests play critical roles not only in the identification/management of individuals infected by SARS-CoV-2, but also in fast and effective public health surveillance, containment, and response. Our aim has been to develop a fast and robust fluorescence in situ hybridization (FISH) detection method for detecting SARS-CoV-2 RNAs by using an HEK 293 T cell culture model. At various times after being transfected with SARS-CoV-2 E and N plasmids, HEK 293 T cells were fixed and then hybridized with ATTO-labeled short DNA probes (about 20 nt). At 4 h, 12 h, and 24 h after transfection, SARS-CoV-2 E and N mRNAs were clearly revealed as solid granular staining inside HEK 293 T cells at all time points. Hybridization time was also reduced to 1 h for faster detection, and the test was completed within 3 h with excellent results. In addition, we have successfully detected 3 mRNAs (E mRNA, N mRNA, and ORF1a (-) RNA) simultaneously inside the buccal cells of COVID-19 patients. Our high-resolution RNA FISH might significantly increase the accuracy and efficiency of SARS-CoV-2 detection, while significantly reducing test time. The method can be conducted on smears containing cells (e.g., from nasopharyngeal, oropharyngeal, or buccal swabs) or smears without cells (e.g., from sputum, saliva, or drinking water/wastewater) for detecting various types of RNA viruses and even DNA viruses at different timepoints of infection.

The influence of charge on the translation of the sandwich ELISA approach to electronic biosensors

The sandwich approach, whereby an antigen is captured by a primary antibody and detected by a secondary antibody, is commonly used to improve the selectivity and sensitivity of enzyme-linked immunosorbent assays (ELISA). This work details the experimental factors that impact the reliable translation of this sandwich approach to two commonly used electronic biosensors, namely potentiometric and impedimetric biosensors. Previous studies have demonstrated the Debye screening limitations associated with potentiometric biosensors. However, the correlation between the ionic strength of the measurement buffer and the impedimetric biosensing response has not been studied. Potentiometric biosensors were able to successfully detect the primary antibody and the target antigen by decreasing the ionic strength of the phosphate buffered saline (PBS) measurement buffer from 1x PBS to 0.01x PBS. However, the secondary antibody used for the selective signal amplification was not reliably detected. Therefore, the sandwich approach is not viable for potentiometric sensing at biologically relevant ionic strengths, due to the Debye screening effect. Alternatively, decreasing the ionic strength of the measurement buffer allowed for the successful translation of the sandwich approach to impedimetric biosensors. Impedimetric biosensing literature typically attributes a measured increase in the charge transfer resistance to an increase in the thickness of the immobilized biolayer. However, this work highlights the influence that both the charge and thickness of the biolayer have on the transport of the redox couple. Decreasing the ionic strength of the measurement buffer lowers the molecular charge screening effect. This permits the transport of a positively charged redox probe through a negatively charged immobilized biolayer via migration and diffusion. The results demonstrate that the use of a buffer at a lower, yet biologically relevant ionic strength allows for the successful translation of the sandwich approach to impedimetric biosensors.

Toward better pandemic governance and preparedness: South Korea's whole-of-nation approach to COVID-19

BACKGROUND

The profound impact of coronavirus disease (COVID-19) has led to an increased demand for sustainable pandemic governance practices. This study explored emerging hybrid governance practices that provide robust evidence on how to address the complex challenges of pandemics effectively. South Korea, which was severely affected by COVID-19, has implemented a novel governance approach using a whole-of-nation (WoN) model. This hybrid pandemic governance approach, which integrates both whole-of-government and whole-of-society approaches, has enabled synergistic and cohesive multi-sectoral coordination among all stakeholders (public authorities, private enterprises, and civil society) to address multifaceted challenges collectively and strengthen their resilience capacity. This study investigated South Korea's WoN practices and their embedded context and identified key governance enablers facilitating this approach.

METHODS

This study employed a case study design based on an extensive analysis of policy and program documents, drawing on South Korea's publicly available data from January 1, 2020 to March 30, 2023. It assessed six system-level collaborative pandemic governance practices and key enablers, all of which were intended to fortify the country's pandemic response.

RESULTS

The primary areas of the country's WoN governance practices for COVID-19 control were (i) whole-of-government policy-making and response, (ii) COVID-19 testing system, (iii) digital surveillance of COVID-19, (iv) COVID-19 triage and treatment system, (v) domestic vaccine production, and (vi) community engagement. Key governance enablers for implementing the WoN model were establishing a legal foundation, ensuring decisive and strong governance and leadership, increasing public investment, applying a whole-of-health approach with augmented investment in public health, enhancing crisis communication, and mobilizing local leaders and civil society organizations in the national public health response.

CONCLUSIONS

In exploring innovative approaches to pandemic governance for increased efficacy, responsiveness, and impact, the WoN approach emerged as highly relevant. This example of emerging practice allows policy-makers to re-evaluate their governance strategies and initiatives to improve multi-agency partnerships across the country in their pandemic-preparedness planning.

Meta-Analysis of the Global Mortality Rate Due to Infection in Burn Patients Admitted for Plastic Surgery

Burn patients are generally prone to infection, which causes the patient's condition to be even worse. However, there is no study regarding the difference between the mortality rate of infected and non-infected patients. Therefore, the aim was to identify and compare the global mortality rate between infected and non-infected patients who were admitted to plastic surgery units. We searched PubMed, ScienceDirect, and Google Scholar and finally included five articles for this meta-analysis. We determined the odds ratio (OR) value by forest plot and assessed the study bias by a funnel plot. We also analyzed the quality and heterogeneity. The OR was determined as 0.43 (95%CI: 0.07-2.60), indicating a higher mortality rate in infected burn patients as compared to non-infected patients. The funnel plot showed no significant study bias. The quality of the studies was assessed high as well, and the heterogeneity was determined significant (I2>75%). The sensitivity analysis with the fixed effect model reconfirmed our main outcome. However, as a study limitation, we could not specifically determine the impact of strain-specific infection on the mortality rate and could not find more relevant research regarding this issue. We conclude that the overall non-infected burn patient mortality rate is lower as compared to the infected burn patients; however, non-infected patients can be prone to death if the burn degree is higher, the respiratory organ is injured, or the treatment is poor or delayed.

L, Olusola T, Ntoimo L, Olugbile M, Opayele AV, Kida I, David S, Onyeaghala A, Igbarumah I, Maduka O, Mahmoud MA, El-Fulatty AR, Olaleye DO, Simon O, Osaigbovo II, Obaseki DE, Tolulupe A, Happi C, Jibrin YB, Okonofua F, Eliya T, Simji G, Abi IJ, Ameh E, Maigari IM, Alhaji S, Adetifa I, Salako B, Bogoro S, Ihekweazu C, Odaibo GN. Performance evaluation of SARS-CoV-2 rapid diagnostic tests in Nigeria: A cross-sectional study

The COVID-19 pandemic challenged health systems globally. Reverse transcription polymerase chain reaction (RT-PCR) is the gold standard for detecting the presence of SARS-CoV-2 in clinical samples. Rapid diagnostic test (RDT) kits for COVID-19 have been widely used in Nigeria. This has greatly improved test turnover rates and significantly decreased the high technical demands of RT-PCR. However, there is currently no nationally representative evaluation of the performance characteristics and reliability of these kits. This study assessed the sensitivity, specificity, and predictive values of ten RDT kits used for COVID-19 testing in Nigeria. This large multi-centred cross-sectional study was conducted across the 6 geo-political zones of Nigeria over four months. Ten antigen (Ag) and antibody (Ab) RDT kits were evaluated, and the results were compared with RT-PCR. One thousand, three hundred and ten (1,310) consenting adults comprising 767 (58.5%) males and 543 (41.5%) females participated in the study. The highest proportion, 757 (57.7%), were in the 20-39 years' age group. In terms of diagnostic performance, Lumira Dx (61.4, 95% CI: 52.4-69.9) had the highest sensitivity while MP SARS and Panbio (98.5, 95% CI: 96.6-99.5) had the highest specificity. For predictive values, Panbio (90.7, 95% CI: 79.7-96.9) and Lumira Dx (81.2, 95% CI: 75.9-85.7) recorded the highest PPV and NPV respectively. Ag-RDTs had better performance characteristics compared with Ab-RDTs; however, the sensitivities of all RDTs in this study were generally low. The relatively high specificity of Ag-RDTs makes them useful for the diagnosis of infection in COVID-19 suspected cases where positive RDT may not require confirmation by molecular testing. There is therefore the need to develop RDTs in-country that will take into consideration the unique environmental factors, interactions with other infectious agents, and strains of the virus circulating locally. This may enhance the precision of rapid and accurate diagnosis of COVID-19 in Nigeria.

Comparative Analysis of the Clinical Presentation of Individuals Who Test Positive or Negative for SARS-CoV-2: Results from a Test Street Study

The common cold, the flu, and the 2019 coronavirus disease (COVID-19) have many symptoms in common. As such, without testing for severe-acute-respiratory-syndrome-related coronavirus 2 (SARS-CoV-2), it is difficult to conclude whether or not one is infected with SARS-CoV-2. The aim of the current study was to compare the presence and severity of COVID-19-related symptoms among those who tested positive or negative for the beta variant of SARS-CoV-2 (B.1.351) and identify the clinical presentation with the greatest likelihood of testing positive for SARS-CoV-2. n = 925 individuals that were tested for SARS-CoV-2 at Dutch mass testing sites (i.e., test streets) were invited to complete a short online survey. The presence and severity of 17 COVID-19-related symptoms were assessed. In addition, mood, health correlates, and quality of life were assessed for the week before the test. Of the sample, n = 88 tested positive and n = 837 tested negative for SARS-CoV-2. Individuals who tested positive for SARS-CoV-2 reported experiencing a significantly greater number, as well as greater overall symptom severity, compared to individuals who tested negative for SARS-CoV-2. A binary logistic regression analysis revealed that increased severity levels of congestion, coughing, shivering, or loss of smell were associated with an increase in the odds of testing positive for SARS-CoV-2, whereas an increase in the severity levels of runny nose, sore throat, or fatigue were associated with an increase in the odds of testing negative for SARS-CoV-2. No significant differences in mood or health correlates were found between those who tested positive or negative for SARS-CoV-2, except for a significantly higher stress score among those who tested negative for SARS-CoV-2. In conclusion, individuals that tested positive for SARS-CoV-2 experienced a significantly greater number and more severe COVID-19-related symptoms compared to those who tested negative for SARS-CoV-2. Experiencing shivering and loss of smell may be the best indicators for increased likelihood of testing positive for SARS-CoV-2.

Surface-engineered natural fibers: Emerging alternative substrates for chemical sensor applications: A review

Natural fiber has become one of the most widely used alternative materials for chemical sensor fabrication due to its advantages, such as biocompatibility, flexibility, and self-microfluidic properties. Enhanced natural fiber surface has been used as a substrate in colorimetric and electrochemical sensors. This review focuses on improving the natural fiber properties for preparation as a substrate for chemical sensors. Various methods for natural fiber extraction are discussed and compared. Bleaching and decolorization is important for preparation of colorimetric sensors, while carbonization and nanoparticle doping are favorable for increasing their electrical conductivity for electrochemical sensor fabrication. Also, example fabrications and applications of natural fiber-based chemical sensors for chemical and biomarker detection are discussed. The selectivity of the sensors can be introduced and improved by surface modification of natural fiber, such as enzyme immobilization and biorecognition element functionalization, illustrating the adaptability of natural fiber as a smart sensing device, e.g., wearable and portable sensors. Ultimately, the high performances of natural fiber-based chemical sensors indicate the potential uses of natural fiber as a renewable and eco-friendly substrate material in the field of chemical sensors and biosensors for clinical diagnosis and environmental monitoring.

Clinical accuracy of instrument-based SARS-CoV-2 antigen diagnostic tests: a systematic review and meta-analysis

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.

Modelling a two-stream emergency department segregation and admission system from COVID-19 early rapid antigen testing: A pilot study

OBJECTIVE

Many factors influence patient flow through an ED, including streaming, treatment spaces and staff resources. This pilot study explored and compared real time patient flow using a single-stream system versus varying configurations of possible two-stream systems using computer simulation.

METHODS

Simulation modelling was used to assess the delay in treatment of a rapid-antigen-tested-based, two-stream model for patient flow through ED during the peak phase of the COVID pandemic.

RESULTS

Modelling two-stream configuration for all patients (minimum time to be seen for both COVID-positive and COVID-negative patients) showed that in the case study ED, a two-stream system and linked changes in bed configuration for managing the risks of infection can impact delays in treatment.

CONCLUSIONS

Data-driven modelling within specific clinical settings can inform the (in)efficiency of patient flow processes and help clinicians and managers make evidence-based decisions about patient transition through EDs. This can assist with reconfiguration of ED patient streaming particularly during periods of unique need, such as the recent COVID-19 pandemic.

Use of telemedicine to tackle health problems in South Asia during the COVID-19 era and beyond: a systematic review

Introduction

Telemedicine (TM) and teleconsultation services flourished during coronavirus disease 2019 (COVID-19) transmission to avoid COVID-19 infection and physical contact. Many physicians switched to the virtual treatment mode and nearly all types of health disciplines were covered. Through this systematic review, the authors tried to explore the strengths and weaknesses of TM, identify the barriers to adopting TM by population, and explain the limitations of this healthcare delivery model.

Methods and results

In this systematic review, 28 studies were included (>53% high-quality studies) as eligible, where nearly 75% (n=21) of the studies were from India, and the remaining 25% (n=7) were from Pakistan, Bangladesh, Sri Lanka, and Nepal. Advice related to cancer, autoimmune diseases, and neurological diseases were the most common among the health disciplines in which TM was used. A peak in teleconsultation was observed during the high transmission phase of COVID-19, although major queries were associated with existing health complications and comorbidities.

Conclusion

Other than a few concerns regarding connectivity, privacy, and diagnosis, TM was in fact affordable, timesaving, feasible, and accurate, which ensured a highly satisfying experience among the participants (>80%).

Clinical Performance of the Reverse Transcription-Loop-Mediated Isothermal Amplification Assay for the Diagnosis of COVID-19 in a Thai Community Hospital at the Thailand-Myanmar Border

INTRODUCTION

Coronavirus disease 2019 (COVID-19) continues to be a global health threat and is a public health issue in Thailand and other countries. The extensive cross-border between Thailand and Myanmar is considered to be at a potentially high risk for COVID-19 distribution in this region. In this instance, simple and cost-effective tests for rapid and early detection of COVID-19 would be useful for effective patient management and control of the disease.

METHODS

This study was conducted at Mae Sot Hospital on the border of Thailand-Myanmar to evaluate the diagnostic performance of a simple colorimetric reverse transcription-loop-mediated isothermal amplification (RT-LAMP) assay developed recently for the rapid detection of SARS-CoV-2. Nasopharyngeal specimens were routinely collected and processed through automated nucleic acid extraction followed by real-time reverse transcription-polymerase chain reaction (rRT-PCR) using the Molaccu® COVID-19 Detection Kit. The RT-LAMP assay was further performed on remnant RNA samples, and the visual results were compared to those of rRT-PCR as a reference.

RESULTS

Of the 727 samples tested, the RT-LAMP assay could detect 322 out of 374 samples positive for SARS-CoV-2 by rRT-PCR with 100% (n = 353/353) negative agreement. The comparative analysis demonstrated the overall accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of the RT-LAMP at 92.85% (n = 675/727, 95% CI: 90.73-94.61), 86.10% (n = 322/374, 95% CI: 82.17-89.44), 100% (n = 353/353, 95% CI: 98.96-100), 100% (n = 322/322, 95% CI: 98.86-100), and 87.16% (n = 353/405, 95% CI: 84.06-89.73), respectively.

CONCLUSION

This RT-LAMP assay showed good diagnostic performance in the hospital setting. It can increase laboratory capacity for rapid SARS-CoV-2 testing and has the potential for use as an alternative or a backup assay at the point of need, especially where alternatives are unavailable for any reason, such as a decline in COVID-19 cases.

UbiNAAT: a multiplexed point-of-care nucleic acid diagnostic platform for rapid at-home pathogen detection

The COVID-19 pandemic increased demands for respiratory disease testing to facilitate treatment and limit transmission, demonstrating in the process that most existing test options were too complex and expensive to perform in point-of-care or home scenarios. Lab-based molecular techniques can detect viral RNA in respiratory illnesses but are expensive and require trained personnel, while affordable antigen-based home tests lack sensitivity for early detection in newly infected or asymptomatic individuals. The few home RNA detection tests deployed were prohibitively expensive. Here, we demonstrate a point-of-care, paper-based rapid analysis device that simultaneously detects multiple viral RNAs; it is demonstrated on two common respiratory viruses (COVID-19 and influenza A) spiked onto a commercial nasal swab. The automated device requires no sample preparation by the user after insertion of the swab, minimizing user operation steps. We incorporated lyophilized amplification reagents immobilized in a porous matrix, a novel thermally actuated valve for multiplexed fluidic control, a printed circuit board that performs on-device lysis and amplification within a cell-phone-sized disposable device. Reverse transcription loop-mediated isothermal amplification (RT-LAMP) products are visualized via fluorescent dyes using a modified cell phone, resulting in detection of as few as 104 viral copies per swab across both pathogens within 30 minutes. This integrated platform could be commercialized in a form that would be inexpensive, portable, and sensitive; it can readily be multiplexed to detect as many as 8 different RNA or DNA sequences, and adapted to any desired RNA or DNA detection assays.

A single-center experience on long-term clinical performance of a rapid SARS-CoV-2 Antigen Detection Test, STANDARD Q COVID-19 Ag Test

The COVID-19 pandemic in Korea has dynamically changed with the occurrence of more easily transmissible variants. A rapid and reliable diagnostic tool for detection of SARS-CoV-2 is needed. While RT-PCR is currently the gold standard for detecting SARS-CoV-2, the procedure is time-consuming and requires expert technicians. The rapid antigen detection test (RADT) was approved as a confirmatory test on 14 March 2022 due to rapid dissemination of the Omicron variant. The benefits of the RADT are speed, simplicity, and point-of-care feasibility. The aim of our study was to evaluate the clinical performance of RADT compared to RT-PCR in a single center over 15 months, fully covering the SARS-CoV-2 'Variants of Concern (VOC).' A total of 14,194 cases was simultaneously tested by RT-PCR and RADT from January 2021 to March 2022 in Gangnam Severance Hospital and were retrospectively reviewed. PowerChek SARS-CoV-2, Influenza A&B Multiplex Real-time PCR Kit, and STANDARD Q COVID-19 Ag Test were used. Positive rates, sensitivities, specificities, positive predictive values (PPV), and negative predictive values (NPV) were estimated for five periods (3 months/period). Receiver operator characteristic curve (ROC) analysis was performed, and Spearman's rank test assessed the correlation between RT-PCR Ct values and semi-quantitative RADT results. The overall positive rate of RT-PCR was 4.64%. The overall sensitivity and specificity were 0.577 [95% confidence interval (CI) 0.539-0.614] and 0.991 [95% CI 0.989-0.993], respectively. ROC analysis resulted in an area under the curve of 0.786 (P < 0.0001, Yuden's index = 0.568). The PCR positive rates were estimated as 0.11%, 0.71%, 4.51%, 2.02%, and 13.72%, and PPV was estimated as 0.045, 0.421, 0.951, 0.720, and 0.798 in Periods 1, 2, 3, 4, and 5, respectively. A significant and moderate negative correlation between PCR Ct values and semi-quantitative RADT results was observed (Spearman's ρ = - 0.646, P < 0.0001). The RADT exhibited good performance in specimens with low Ct values (Ct ≤ 25.00) by RT-PCR. The PPV was significantly higher in Periods 3 and 5, which corresponds to rapid dissemination of the Delta and Omicron variants. The high PPV implies that individuals with a positive RADT result are very likely infected with SARS-CoV-2 and would require prompt quarantine rather than additional RT-PCR testing. The sensitivity of 0.577 indicates that RADT should not replace RT-PCR. Nonetheless, given the high PPV and the ability to track infected persons through rapid results, our findings suggest that RADT could play a significant role in control strategies for further SARS-CoV-2 variants.

Ten rapid antigen tests for SARS-CoV-2 widely differ in their ability to detect Omicron-BA.4 and -BA.5

Since late 2021, the variant landscape of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been dominated by the variant of concern (VoC) Omicron and its sublineages. We and others have shown that the detection of Omicron-BA.1 and -BA.2-positive respiratory specimens by rapid antigen tests (RATs) is impaired compared to Delta VoC-containing samples. Here, in a single-center retrospective laboratory study, we evaluated the performance of ten most commonly used RATs for the detection of Omicron-BA.4 and -BA.5 infections. We used 171 respiratory swab specimens from SARS-CoV-2 RNA-positive patients, of which 71 were classified as BA.4 and 100 as BA.5. All swabs were collected between July and September 2022. 50 SARS-CoV-2 PCR-negative samples from healthy individuals, collected in October 2022, showed high specificity in 9 out of 10 RATs. When assessing analytical sensitivity using clinical specimens, the 50% limit of detection (LoD50) ranged from 7.6 × 104 to 3.3 × 106 RNA copies subjected to the RATs for BA.4 compared to 6.8 × 104 to 3.0 × 106 for BA.5. Overall, intra-assay differences for the detection of these two Omicron subvariants were not significant for both respiratory swabs and tissue culture-expanded virus isolates. In contrast, marked heterogeneity was observed among the ten RATs: to be positive in these point-of-care tests, up to 443-fold (BA.4) and up to 56-fold (BA.5) higher viral loads were required for the worst performing RAT compared to the best performing RAT. True-positive rates for Omicron-BA.4- or -BA.5-containing specimens in the highest viral load category (Ct values < 25) ranged from 94.3 to 34.3%, dropping to 25.6 to 0% for samples with intermediate Ct values (25-30). We conclude that the high heterogeneity in the performance of commonly used RATs remains a challenge for the general public to obtain reliable results in the evolving Omicron subvariant-driven pandemic.

A Single-Tube Colorimetric Loop-Mediated Isothermal Amplification for Rapid Detection of SARS-CoV-2 RNA

Since SARS-CoV-2 is a highly transmissible virus, a rapid and accurate diagnostic method is necessary to prevent virus spread. We aimed to develop and evaluate a new rapid colorimetric reverse transcription loop--mediated isothermal amplification (RT-LAMP) assay for SARS-CoV-2 detection in a single closed tube. Nasopharyngeal and throat swabs collected from at-risk individuals testing for SARS-CoV-2 were used to assess the sensitivity and specificity of a new RT-LAMP assay against a commercial qRT-PCR assay. Total RNA extracts were submitted to the RT-LAMP reaction under optimal conditions and amplified at 65 °C for 30 min using three sets of specific primers targeting the nucleocapsid gene. The reaction was detected using two different indicator dyes, hydroxynaphthol blue (HNB) and cresol red. A total of 82 samples were used for detection with HNB and 94 samples with cresol red, and results were compared with the qRT-PCR assay. The sensitivity of the RT-LAMP-based HNB assay was 92.1% and the specificity was 93.2%. The sensitivity of the RT-LAMP-based cresol red assay was 80.3%, and the specificity was 97%. This colorimetric feature makes this assay highly accessible, low-cost, and user-friendly, which can be deployed for massive scale-up and rapid diagnosis of SARS-CoV-2 infection, particularly in low-resource settings.

Canine olfactory detection of SARS-CoV-2-infected humans-a systematic review

PURPOSE

To complement conventional testing methods for severe acute respiratory syndrome coronavirus type 2 infections, dogs' olfactory capability for true real-time detection has been investigated worldwide. Diseases produce specific scents in affected individuals via volatile organic compounds. This systematic review evaluates the current evidence for canine olfaction as a reliable coronavirus disease 2019 screening tool.

METHODS

Two independent study quality assessment tools were used: the QUADAS-2 tool for the evaluation of laboratory tests' diagnostic accuracy, designed for systematic reviews, and a general evaluation tool for canine detection studies, adapted to medical detection. Various study design, sample, dog, and olfactory training features were considered as potential confounding factors.

RESULTS

Twenty-seven studies from 15 countries were evaluated. Respectively, four and six studies had a low risk of bias and high quality: the four QUADAS-2 nonbiased studies resulted in ranges of 81%-97% sensitivity and 91%-100% specificity. The six high-quality studies, according to the general evaluation system, revealed ranges of 82%-97% sensitivity and 83%-100% specificity. The other studies contained high bias risks and applicability and/or quality concerns.

CONCLUSIONS

Standardization and certification procedures as used for canine explosives detection are needed for medical detection dogs for the optimal and structured usage of their undoubtful potential.

Performance of Reverse Transcription Loop-Mediated Isothermal Amplification (RT-LAMP) Targeting the RNA Polymerase Gene for the Direct Detection of SARS-CoV2 in Nasopharyngeal Swabs

In 2020, a global pandemic caused by SARS-CoV-2 was declared. Different institutes proposed diagnostic molecular methods to detect the virus in clinical samples. This study aims to validate and standardize the use of a loop-mediated isothermal amplification (LAMP)-based methodology targeting the viral RP gene, as a faster and low-cost diagnostic method for SARS-CoV-2 infections. The results obtained with RT-LAMP (Reverse Transcriptase) were compared to the results of real-time polymerase chain reaction (RT-PCR) to assess its sensitivity and specificity. In total, 115 samples (nasopharyngeal samples) were used for detecting SARS-CoV-2 by RT-LAMP, with 43 positives and 72 negatives. The study showed a positive predictive value (PPV) of 90.7% and a negative predictive value (VPN) of 100%. The LAMP assay also demonstrated a high sensitivity of 90.7% and a specificity of 100% (confidence interval 77.9-97.4%) when using the lower detection limit of 40 copies/µL. The RT-LAMP described here has the potential to detect even the new variants of SARS-CoV-2, suggesting that it may not be significantly affected by gene mutations. The RT-LAMP targeting the RP viral region is faster and less expensive than other molecular approaches, making it an alternative for developing countries.

Association Between Rapid Antigen Detection Tests and Real-Time Reverse Transcription-Polymerase Chain Reaction Assay for SARS-CoV-2: A Systematic Review and Meta-Analyses

Objectives: We aimed to assess the association between rapid antigen detection tests and real-time reverse transcription-polymerase chain reaction assay for severe acute respiratory syndrome coronavirus 2. Methods: We searched PubMed, Cochrane Library, EMBASE, and the Web of Science from their inception to 31 May 2023. A random-effects meta-analysis was used to estimate false positives in the RADTs group, relative to those in the RT-PCR group, and subgroup analyses were conducted based on the different Ct value cut-offs (<40 or ≥40). We performed this study in accordance with the guidelines outlined in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Results: Fifty-one studies were included and considered to be of moderate quality. We found a satisfactory overall false positive rate (0.01, 95% CI: 0.00-0.01) for the RADTs compared to RT-PCR. In the stratified analysis, we also found that the false positive rates of the RADTs did not increase when Ct values of RT-PCR (Ct < 40, 0.01, 95% CI: 0.00-0.01; Ct ≥ 40, 0.01, 95% CI: 0.00-0.01). Conclusion: In conclusion, the best available evidence supports an association between RADTs and RT-PCR. When Ct-values were analyzed using cut-off <40 or ≥40, this resulted in an estimated false positive rate of only 1%.

Radu E, Matei L, Maria Ruta S, Bleotu C. SARS-CoV-2 Variant Surveillance in Genomic Medicine Era

In the genomic medicine era, the emergence of SARS-CoV-2 was immediately followed by viral genome sequencing and world-wide sequences sharing. Almost in real-time, based on these sequences, resources were developed and applied around the world, such as molecular diagnostic tests, informed public health decisions, and vaccines. Molecular SARS-CoV-2 variant surveillance was a normal approach in this context yet, considering that the viral genome modification occurs commonly in viral replication process, the challenge is to identify the modifications that significantly affect virulence, transmissibility, reduced effectiveness of vaccines and therapeutics or failure of diagnostic tests. However, assessing the importance of the emergence of new mutations and linking them to epidemiological trend, is still a laborious process and faster phenotypic evaluation approaches, in conjunction with genomic data, are required in order to release timely and efficient control measures.

Rapid antigen-based and rapid molecular tests for the detection of SARS-CoV-2: a rapid review with network meta-analysis of diagnostic test accuracy studies

BACKGROUND

The global spread of COVID-19 created an explosion in rapid tests with results in < 1 hour, but their relative performance characteristics are not fully understood yet. Our aim was to determine the most sensitive and specific rapid test for the diagnosis of SARS-CoV-2.

METHODS

Design: Rapid review and diagnostic test accuracy network meta-analysis (DTA-NMA).

ELIGIBILITY CRITERIA

Randomized controlled trials (RCTs) and observational studies assessing rapid antigen and/or rapid molecular test(s) to detect SARS-CoV-2 in participants of any age, suspected or not with SARS-CoV-2 infection.

INFORMATION SOURCES

Embase, MEDLINE, and Cochrane Central Register of Controlled Trials, up to September 12, 2021.

OUTCOME MEASURES

Sensitivity and specificity of rapid antigen and molecular tests suitable for detecting SARS-CoV-2. Data extraction and risk of bias assessment: Screening of literature search results was conducted by one reviewer; data abstraction was completed by one reviewer and independently verified by a second reviewer. Risk of bias was not assessed in the included studies.

DATA SYNTHESIS

Random-effects meta-analysis and DTA-NMA.

RESULTS

We included 93 studies (reported in 88 articles) relating to 36 rapid antigen tests in 104,961 participants and 23 rapid molecular tests in 10,449 participants. Overall, rapid antigen tests had a sensitivity of 0.75 (95% confidence interval 0.70-0.79) and specificity of 0.99 (0.98-0.99). Rapid antigen test sensitivity was higher when nasal or combined samples (e.g., combinations of nose, throat, mouth, or saliva samples) were used, but lower when nasopharyngeal samples were used, and in those classified as asymptomatic at the time of testing. Rapid molecular tests may result in fewer false negatives than rapid antigen tests (sensitivity: 0.93, 0.88-0.96; specificity: 0.98, 0.97-0.99). The tests with the highest sensitivity and specificity estimates were the Xpert Xpress rapid molecular test by Cepheid (sensitivity: 0.99, 0.83-1.00; specificity: 0.97, 0.69-1.00) among the 23 commercial rapid molecular tests and the COVID-VIRO test by AAZ-LMB (sensitivity: 0.93, 0.48-0.99; specificity: 0.98, 0.44-1.00) among the 36 rapid antigen tests we examined.

CONCLUSIONS

Rapid molecular tests were associated with both high sensitivity and specificity, while rapid antigen tests were mainly associated with high specificity, according to the minimum performance requirements by WHO and Health Canada. Our rapid review was limited to English, peer-reviewed published results of commercial tests, and study risk of bias was not assessed. A full systematic review is required.

REVIEW REGISTRATION

PROSPERO CRD42021289712.

Analysis of the Virus SARS-CoV-2 as a Potential Bioweapon in Light of International Literature

INTRODUCTION

As of early 2022, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic still represents a worldwide medical emergency situation. The ongoing vaccination programs can slow down the spread of the virus; however, from time to time, the newly emerging variants of concern and antivaccination movements carry the possibility for the disease to remain in our daily lives. After the appearance of SARS-CoV-2, there was scholarly debate whether the virus was of natural origin, or it emerged from a laboratory, some even thinking the agent's potential biological weapon properties suggest the latter scenario. Later, the bioweapon theory was dismissed by the majority of experts, but the question remains that despite its natural origin, how potent a biological weapon the SARS-CoV-2 virus can become over time.

MATERIALS AND METHODS

Based on 12 bioweapon threat assessment criteria already published in 2018, we performed a literature search and review, focusing on relevant potential bioweapon properties of the virus SARS-CoV-2. Instead of utilizing a survey among experts, we tried to qualify and quantify characteristics according to the available data found in peer-reviewed papers. We also identified other key elements not mentioned in the original 12 bioweapon criteria, which can play an important role in assessing future biological weapons.

RESULTS

According to the international literature we analyzed, SARS-CoV-2 is a moderately infectious agent (ID50 estimated between 100 and 1,000), with high infection-to-disease ratio (35%-45% rate of asymptomatic infected) and medium incubation period (1-34 days, mean 6-7 days). Its morbidity and mortality rate can be categorized as medium (high morbidity rate with significant mortality rate). It can be easily produced in large quantities, has high aerosol stability, and has moderate environmental stability. Based on laboratory experiments and statistical model analysis, it can form and is contagious with droplet nuclei, and with spray technique utilization, it could be weaponized effectively. Several prophylactic countermeasures are available in the form of vaccines; however, specific therapeutic options are much more limited. In connection with the original assessment criteria, the SARS-CoV-2 only achieved a "0" score on the ease of detection because of readily available, relatively sensitive, and specific rapid antigen tests. Based on the pandemic experience, we also propose three new assessment categories: one that establishes a mean to measure the necessary quarantine restrictions related to a biological agent, another one that can represent the personal protective equipment required to work safely with a particular agent, and a third one that quantifies the overall disruptive capability, based on previous real-life experiences. These factors could further specify the threat level related to potential biological weapons.

CONCLUSIONS

Our results show that the virus can become a potent bioweapon candidate in the future, achieving a total score of 24 out of 36 on the original 12 criteria. The SARS-CoV-2 has already proven its pandemic generating potential and, despite worldwide efforts, still remains an imminent threat. In order to be prepared for the future possibility of the virus arising as a bioweapon, we must remain cautious and take the necessary countermeasures.

Economical and Easily Obtainable Tools to Manually Develop Lateral Flow Immunoassay Strips

The development of inexpensive and highly functional lateral flow devices, which utilize simple and affordable tools, can make them accessible to many populations with insufficient resources. Therefore, this study aims to provide a method to overcome the cost challenges associated with using expensive manufacturing technologies and machinery, particularly during pandemics and upon urgent need. Here, in-house lateral flow strips to detect serum antibodies were developed using low-priced and easily available tools such as adhesive tape and CytoSep layers. The developed lateral flow immunoassay strips presented here produced signals with 93.3 and 96.6% sensitivity for SARS-CoV-2 nucleocapsid protein-specific IgM and IgG antibodies, respectively. The specificity obtained from the developed strips was 96.6% for SARS-CoV-2 nucleocapsid protein-specific IgM and 100% for the IgG antibodies by applying only 5 μL from the serum samples. The proposed design was entirely made manually to ensure a method that would make lateral flow devices available to many populations in need around the globe.

Clinical performance of rapid antigen tests in comparison to RT-PCR for SARS-COV-2 diagnosis in Omicron variant: A systematic review and meta-analysis

The Omicron variant of concern has a high level of mutations in different genes that has raised awareness about the performance of immunological products such as vaccines and antigen detection kits. In this systematic review and meta-analysis, we investigated whether Omicron had a significant influence on rapid antigen test (RAT) performance in comparison to PCR. We registered this systematic review and meta-analysis in PROSPERO with the registration number CRD42022355510. We searched PubMed, Scopus, Embase, and Web of Science databases systematically to 1 August 2022. After article screening, we assessed the quality of the included studies based on the JBI checklist. Following data extraction, we performed a meta-analysis using R software. We included 18 qualified articles presenting sufficient data about RATs performance in comparison to RT-PCR in Omicron infections. The pooled specificity and sensitivity of RATs were 1.000 (0.997-1.000) and 0.671 (0.595-0.721), respectively. The FDA-approved kits showed a better performance than WHO-approved ones with a sensitivity of 0.728 (0.620-0.815). The use of RATs with nasal swabs showed a higher sensitivity compared with nasopharyngeal swabs. The sensitivity for samples with a CT-value >25 was 0.108 (0.048-0.227). Rapid antigen tests show impaired performance for COVID-19 diagnosis when the Omicron variant is circulating, particularly in samples with low viral loads.

Diagnostic, Prognostic and Mechanistic Biomarkers of COVID-19 Identified by Mass Spectrometric Metabolomics

A number of studies have assessed the impact of SARS-CoV-2 infection and COVID-19 severity on the metabolome of exhaled air, saliva, plasma, and urine to identify diagnostic and prognostic biomarkers. In spite of the richness of the literature, there is no consensus about the utility of metabolomic analyses for the management of COVID-19, calling for a critical assessment of the literature. We identified mass spectrometric metabolomic studies on specimens from SARS-CoV2-infected patients and subjected them to a cross-study comparison. We compared the clinical design, technical aspects, and statistical analyses of published studies with the purpose to identify the most relevant biomarkers. Several among the metabolites that are under- or overrepresented in the plasma from patients with COVID-19 may directly contribute to excessive inflammatory reactions and deficient immune control of SARS-CoV2, hence unraveling important mechanistic connections between whole-body metabolism and the course of the disease. Altogether, it appears that mass spectrometric approaches have a high potential for biomarker discovery, especially if they are subjected to methodological standardization.

The global prevalence of vestibular dysfunction in children and adolescents: a systematic review and meta-analysis

BACKGROUND

Vestibular dysfunction has been extensively studied amongst the older population. Recently, conditions and management of vestibular dysfunction among children and adolescent has gained attention. Yet, a lack of awareness and expertise in managing children and adolescents with vestibular dysfunction has led to a delay in diagnosis as well as a trifling prevalence rate.

AIM

To conduct a systematic review and meta-analyses to estimate the overall pooled prevalence of vestibular dysfunction in children and adolescents.

METHODS

PubMed, Scopus, and Web of Science databases were searched to identify studies published until 29 April 2022. We used a random-effects model to estimate the pooled prevalence with 95% confidence intervals (CIs). Heterogeneity was assessed using the I² statistic and Cochran's Q test. The robustness of the pooled estimates was checked by different subgroups and sensitivity analyses.

RESULTS

We identified 1811 studies, of which 39 studies (n = 323,663) were included in the meta-analysis. Overall, the pooled prevalence of children and adolescents with VD was 30.4% [95% CI 28.5-32.3%]. The age of the participants ranged from 1 to 19 years. Participants of the included 39 studies were from 15 countries. Among the studies, 34 were cross-sectional, and five were case-control designed. There were discrepancies found in the studies with objective (higher prevalence) versus subjective (lower prevalence) evaluations.

CONCLUSION

The prevalence of VD among children and adolescents was found to be 30.4% based on high-quality evidence. Due to the subjective assessment of most studies pooled in the analysis, the results should be interpreted cautiously until future comparative studies with objective assessments are carried out.

An overview of the most important preanalytical factors influencing the clinical performance of SARS-CoV-2 antigen rapid diagnostic tests (Ag-RDTs)

Due to the many technical limitations of molecular biology, the possibility to sustain enormous volumes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) diagnostic testing relies strongly on the use of antigen rapid diagnostic tests (Ag-RDTs). Besides a limited analytical sensitivity, the manually intensive test procedures needed for performing these tests, very often performed by unskilled personnel or by the patients themselves, may contribute to considerably impair their diagnostic accuracy. We provide here an updated overview on the leading preanalytical drawbacks that may impair SARS-CoV-2 Ag-RDT accuracy, and which encompass lower diagnostic sensitivity in certain age groups, in asymptomatic subjects and those with a longer time from symptoms onset, in vaccine recipients, in individuals not appropriately trained to their usage, in those recently using oral or nasal virucidal agents, in oropharyngeal swabs and saliva, as well as in circumstances when instructions provided by the manufacturers are unclear, incomplete or scarcely readable and intelligible. Acknowledging these important preanalytical limitations will lead the way to a better, more clinically efficient and even safer use of this important technology, which represents an extremely valuable resource for management of the ongoing pandemic.

Order of Occurrence of COVID-19 Symptoms

BACKGROUND AND OBJECTIVES

COVID-19 symptoms change after onset-some show early, others later. This article examines whether the order of occurrence of symptoms can improve diagnosis of COVID-19 before test results are available.

METHODS

In total, 483 individuals who completed a COVID-19 test were recruited through Listservs. Participants then completed an online survey regarding their symptoms and test results. The order of symptoms was set according to (a) whether the participant had a "history of the symptom" due to a prior condition; and (b) whether the symptom "occurred first," or prior to, other symptoms of COVID-19. Two LASSO (Least Absolute Shrinkage and Selection Operator) regression models were developed. The first model, referred to as "time-invariant," used demographics and symptoms but not the order of symptom occurrence. The second model, referred to as "time-sensitive," used the same data set but included the order of symptom occurrence.

RESULTS

The average cross-validated area under the receiver operating characteristic (AROC) curve for the time-invariant model was 0.784. The time-sensitive model had an AROC curve of 0.799. The difference between the 2 accuracy levels was statistically significant (α < .05).

CONCLUSION

The order of symptom occurrence made a statistically significant, but small, improvement in the accuracy of the diagnosis of COVID-19.

Art-science multidisciplinary collaborations to address the scientific challenges posed by COVID-19

The ongoing coronavirus pandemic COVID-19 constitutes a scientific and social challenge. The application of mixed-methods research with multidisciplinary collaborations increases the success of experimental design and interpretation of results to approach scientific challenges. The objective is to develop and implement protean art algorithms with interactions between artists and scientists for scientific research in areas of molecular biology, immunology, ecology and biomedicine. In this perspective, artists were invited to contribute pieces related to the pandemic, and scientists were then challenged to contribute their view and proposed research inspired by artist contribution to face COVID-19 scientific challenges. Proposed research objectives inspired by artist contributions contribute to approach COVID-19 scientific and social challenges with results that may translate into new diagnosis and control interventions. The proposed research objectives approach vaccine protective mechanisms and the development of nutritional interventions with possible impact on boosting protective response to vaccination, the impact of fuel pollutants on host immunity and virus transmission, the possible role of ectoparasite vectors in the appearance of SARS-CoV-2 variants and virus transmission, collaboration between different sectors to contribute to virus surveillance and reduce risks of contagion, characterization of the incidence of zoonotic diseases during and after the COVID-19 pandemic in relation to modifications in the interactions between humans and reservoir animal species, evaluation of the risks associated with sexual or congenital transmission of SARS-CoV-2, development of new methods for the easy and rapid detection of very low SARS-CoV-2 virus amounts in infected but asymptomatic individuals, and understanding society perceptions about the socio-ecological relationships between decoupled environments and the risks and effects of pandemics. This approach may be used to promote social participation in science through combined scientific and artistic perspectives with impact on science and society.KEY MESSAGEMixed-methods research with multidisciplinary collaborations increases the success of experimental design and interpretation of results.Implementation of protean art algorithms through interactions between artists and scientists advances scientific research.Proposed research objectives inspired by artist contributions contribute to approach COVID-19 scientific and social challenges with results that may translate into new diagnosis and control interventions.

Evaluation of Various Alternative Economical and High Throughput SARS-CoV-2 Testing Methods within Resource-Limited Settings

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak posed a challenge for diagnostic laboratories worldwide, with low-middle income countries (LMICs) being the most affected. The polymerase chain reaction (PCR) is the gold standard method for detecting SARS-CoV-2 infection. However, the challenge with this method is that it is expensive, which has resulted in under-testing for SARS-CoV-2 infection in many LMICs. Hence, this study aimed to compare and evaluate alternative methods for the mass testing of SARS-CoV-2 infection in laboratories with limited resources to identify cost-effective, faster, and accurate alternatives to the internationally approved kits. A total of 50 residual nasopharyngeal swab samples were used for evaluation and comparison between internationally approved kits (Thermo Fisher PureLink™ RNA Isolation Kit and Thermo Fisher TaqPath™ COVID-19 Assay Kit) and alternative methods (three RNA extraction and four commercial SARS-CoV-2 RT-PCR assay kits) in terms of the cost analysis, diagnostic accuracy, and turnaround time. In terms of performance, all of the alternative RNA extraction methods evaluated were comparable to the internationally approved kits but were more cost-effective (Lucigen QuickExtract™ RNA Extraction Kit, Bosphore EX-Tract Dry Swab RNA Solution and Sonicator method) and four commercial SARS-CoV-2 RT-PCR assay kits (Nucleic Acid COVID-19 Test Kit (SARS-CoV-2), abTESTM COVID-19 qPCR I Kit, PCL COVID19 Speedy RT-PCR Kit, and PCLMD nCoV One-Step RT-PCR Kit) with a sensitivity range of 76-100% and specificity of 96-100%. The cost per sample was reduced by more than 50% when compared to internationally approved kits. When compared to the Thermo Fisher PureLink™ Kit and Thermo Fisher TaqPath™ COVID-19 Assay Kit, the alternative methods had a faster turnaround time, indicating that laboratories with limited resources may be able to process more samples in a day. The above-mentioned cost-effective, fast, and accurate evaluated alternative methods can be used in routine diagnostic laboratories with limited resources for mass testing for SARS-CoV-2 because these were comparable to the internationally approved kits, Thermo Fisher PureLink™ Kit and Thermo Fisher TaqPath™ COVID-19 Assay Kit. The implementation of alternative methods will be the most cost-effective option for testing SARS-CoV-2 infection in LMICs.

Lateral Flow Immunoassays for Detecting Viral Infectious Antigens and Antibodies

Abundant immunological assays currently exist for detecting pathogens and identifying infected individuals, making detection of diseases at early stages integral to preventing their spread, together with the consequent emergence of global health crises. Lateral flow immunoassay (LFIA) is a test characterized by simplicity, low cost, and quick results. Furthermore, LFIA testing does not need well-trained individuals or laboratory settings. Therefore, it has been serving as an attractive tool that has been extensively used during the ongoing COVID-19 pandemic. Here, the LFIA strip's available formats, reporter systems, components, and preparation are discussed. Moreover, this review provides an overview of the current LFIAs in detecting infectious viral antigens and humoral responses to viral infections.

Diagnostic accuracy of SARS-CoV-2 antigen test in the pediatric population: A systematic review and meta-analysis

BACKGROUND

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has caused the global coronavirus disease 2019 (COVID-19) pandemic. Rapid identification and isolation of patients infected with SARS-CoV-2 are critical methods for blocking COVID-19 transmission. The advantages of antigen tests, such as their relatively low cost and short turnaround time, can contribute to the prompt identification of infectious individuals. However, the diagnostic accuracy of antigen tests for COVID-19 in children remains inconclusive. This meta-analysis aimed to evaluate the diagnostic performance of antigen tests for SARS-CoV-2 in the pediatric population.

METHODS

We conducted a literature search for relevant studies in the PubMed, Embase, Google Scholar, and Biomed Central databases. Studies evaluating the diagnostic accuracy of antigen tests for SARS-CoV-2 in pediatric patients were included. In addition, we included studies that provided sufficient data to construct a 2 × 2 table on a per-patient basis. The final literature search was performed on October 10, 2021. Days after symptom onset, asymptomatic and symptomatic individuals may have been potential sources of heterogeneity. The overall sensitivity and specificity of the antigen tests were generated using a bivariate random-effects model.

RESULTS

Five studies with 4400 participants were included. The meta-analysis of antigen tests generated a pooled sensitivity of 65.9% (95% CI: 52.8%-77.0%) and pooled specificity of 99.9% (95% CI: 98.9%-100.0%). A subgroup analysis of studies reporting antigen test data for symptomatic patients showed a pooled sensitivity of 64.5% and a pooled specificity of 99.7%. The subgroup analysis of studies that included 881 asymptomatic participants generated a pooled sensitivity of 48.4% and a pooled specificity of 99.5%.

CONCLUSION

Antigen tests exhibit moderate sensitivity and high specificity for detecting SARS-CoV-2 in children. Antigen tests might have moderate sensitivity for detecting SARS-CoV-2 in symptomatic children, and serial testing might effectively prevent further SARS-CoV-2 transmission.

Clinical Evaluation of Severe Acute Respiratory Syndrome Coronavirus 2 Rapid Antigen Tests During the Omicron Wave in South Africa

We evaluated the performance of nasal and nasopharyngeal Standard Q COVID-19 [coronavirus disease 2019] Ag tests (SD Biosensor) and the Panbio COVID-19 Ag Rapid Test Device (nasal; Abbott) against the Abbott RealTime severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) assay during the Omicron (clades 21M, 21K, and 21L) wave in South Africa. Overall, all evaluated tests performed well, with high sensitivity (range, 77.78%-81.42%) and excellent specificity values (>99%). The sensitivity of rapid antigen tests increased above 90% in samples with cycle threshold <20, and all 3 tests performed best within the first week after symptom onset.

An Exploration of Nanoparticle-Based Diagnostic Approaches for Coronaviruses: SARS-CoV-2, SARS-CoV and MERS-CoV

The wildfire-like spread of COVID-19, caused by severe acute respiratory syndrome-associated coronavirus-2, has resulted in a pandemic that has put unprecedented stress on the world's healthcare systems and caused varying severities of socio-economic damage. As there are no specific treatments to combat the virus, current approaches to overcome the crisis have mainly revolved around vaccination efforts, preventing human-to-human transmission through enforcement of lockdowns and repurposing of drugs. To efficiently facilitate the measures implemented by governments, rapid and accurate diagnosis of the disease is vital. Reverse-transcription polymerase chain reaction and computed tomography have been the standard procedures to diagnose and evaluate COVID-19. However, disadvantages, including the necessity of specialized equipment and trained personnel, the high financial cost of operation and the emergence of false negatives, have hindered their application in high-demand and resource-limited sites. Nanoparticle-based methods of diagnosis have been previously reported to provide precise results within short periods of time. Such methods have been studied in previous outbreaks of coronaviruses, including severe acute respiratory syndrome-associated coronavirus and middle east respiratory syndrome coronavirus. Given the need for rapid diagnostic techniques, this review discusses nanoparticle use in detecting the aforementioned coronaviruses and the recent severe acute respiratory syndrome-associated coronavirus-2 to highlight approaches that could potentially be used during the COVID-19 pandemic.

Recent advances in PCR-free nucleic acid detection for SARS-COV-2

As the outbreak of Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory disease coronavirus 2 (SARS-COV-2), fast, accurate, and economic detection of viral infection has become crucial for stopping the spread. Polymerase chain reaction (PCR) of viral nucleic acids has been the gold standard method for SARS-COV-2 detection, which, however, generally requires sophisticated facilities and laboratory space, and is time consuming. This review presents recent advances in PCR-free nucleic acid detection methods for SARS-CoV-2, including emerging methods of isothermal amplification, nucleic acid enzymes, electrochemistry and CRISPR.

A rapid One-Pot RNA isolation method for simplified clinical detection of SARS-COV-2 infection in India

Background

With the rapid increase in COVID-19 cases and the discovery of new viral variants within India over multiple waves, the expensive reagents and time-consuming sample pretreatment required for qPCR analysis have led to slower detection of the disease. The vast Indian population demands an inexpensive and competent sample preparation strategy for rapid detection of the disease facilitating early and efficient containment of the disease.

Methods

In this study, we have surveyed the spread of COVID-19 infection over Faridabad, Haryana, India for 6 months. We also devised a simple single-step method for total RNA extraction using a single tube and compared its efficacy with the commercially available RNA isolation kits.

Findings

Our findings suggest that determining Ct values for samples subjected to the One Pot RNA extraction method was as efficient as the commercially available kits but delivers a subtle advantage in a way, by minimizing the cost, labor and sample preparation time.

Conclusion

This novel crude RNA extraction method is stable and capable of operating in developing countries like India for low resource settings, without the use of expensive reagents and instruments. Additionally, this method can be further adapted to pooling samples strategies owing to its high sensitivity.

Point of care molecular and antigen detection tests for COVID-19: current status and future prospects

INTRODUCTION

Detection of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) has been critical to support and management of the COVID-19 pandemic. Point of care testing (POCT) for SARS-CoV-2 has been a widely used tool for detection of SARS-CoV-2.

AREAS COVERED

POCT nucleic acid amplification tests (NAATs) and rapid antigen tests (RATs) have been the most readily used POCT for SARS-CoV-2. Here, current knowledge on the utility of POCT NAATs and RATs for SARS-CoV-2 are reviewed and discussed alongside aspects of quality assurance factors that must be considered for successful and safe implementation of POCT.

EXPERT OPINION

Use cases for implementation of POCT must be evidence based, regardless of the test used. A quality assurance framework must be in place to ensure accuracy and safety of POCT.

Prevalence of Avascular Necrosis Following Surgical Treatments in Unstable Slipped Capital Femoral Epiphysis (SCFE): A Systematic Review and Meta-Analysis

The choice of treatment for unstable and severely displaced slipped capital femoral epiphysis (SCFE) is controversial. This meta-analysis was conducted to determine the prevalence of femoral head avascular necrosis (AVN) following various treatments for unstable SCFE. Various databases were searched to identify articles published until 4 February 2022. A random-effects model was used to examine prevalence as well as risk ratios with confidence intervals (CIs) of 95%. Thirty-three articles were analyzed in this study. The pooled prevalences of AVN in pinning in situ, pinning following intentional closed reduction, pinning following unintentional closed reduction, and open reduction via the Parsch method, subcapital osteotomy and the modified Dunn procedure were 18.5%, 23.0%, 27.6%, 9.9%, 18.6% and 19.9%, respectively. The risk of developing AVN in pinning following intentional closed reduction was found to be 1.62 times higher than pinning in situ; however, this result was not significant. The prevalence of AVN in open reduction was lowest when performed via the Parsch method; however, this finding should be interpreted with caution, since the majority of slips so-treated are of mild and moderate types as compared with the subcapital osteotomy and modified Dunn procedures, which are predominantly used to treat severely displaced slips. As the risk ratio between intentional closed reduction and the modified Dunn method showed no significant difference, we believe that the modified Dunn method has the advantage of meticulously preserving periosteal blood flow to the epiphysis, thus minimizing AVN risk. In comparison with intentional closed reduction, the modified Dunn method is used predominantly in cases of severe slips.

Diagnostic accuracy of rapid antigen test for SARS-CoV-2: A systematic review and meta-analysis of 166,943 suspected COVID-19 patients

To assess the diagnostic accuracy of the rapid antigen test (RAT) compared with RT-PCR (reference standard) for SARS-CoV-2, we searched MEDLINE/PubMed and Web of Science for relevant records. The QUADAS-2 tool was used to assess study quality, and quantitative synthesis was conducted using a bivariate random-effects model. The meta-analysis included 135 studies (166,943 samples). The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were 0.76 (95%CI: 0.73-0.79), 1.00 (95%CI: 1.00-1.00), 276.1 (95% CI, 184.1-414.1), 0.24 (95% CI, 0.21-0.27), and 1171 (95% CI, 782-1755), respectively. Compared to other sample types, nasal samples had the best RAT sensitivity [0.79 (95%CI: 0.71-0.85)]. The sensitivities of the different RAT kits ranged from 0.41 (95%CI: 0.23-0.61) to 0.90 (95%CI: 0.70-0.97). Sensitivity was markedly better in samples with lower Ct, and RAT achieved excellent pooled sensitivity at 1.00 (95%CI: 0.70-1.00) among samples with Ct < 20. Testing within 10 days of symptom onset resulted in a high sensitivity. For ≤ 3, ≤ 7, and ≤ 10 days, the sensitivities were 0.91 (95%CI: 0.83-0.96), 0.89 (95%CI: 0.84-0.93), and 0.88 (95%CI: 0.83-0.92), respectively. RAT kits show high sensitivity and specificity in early infection, especially when the viral load is high. Moreover, using nasal samples for antigen testing, which are moderately sensitive and patient-friendly, is a reliable alternative to nasopharyngeal sampling. RAT might be effective for fighting the COVID-19 pandemic; however, it must be complemented by the careful handling of negative test results.

Comparing Rapid Ag Test and PCR in SARS-CoV-2 Management in Rural Egypt

Like elsewhere around the globe, SARS-CoV-2 infection is spreading in rural Egypt. Due to high sensitivity and specificity, the gold standard of diagnostics is reverse transcription polymerase chain reaction PCR (RT-PCR). Rural areas without access to certified laboratories cannot take advantage of RT-PCR testing, and thus are dependent upon rapid antigen testing, a point-of-care test that requires less training and can produce results within 15 minutes. Rapid antigen testing can give an advantage to medical teams in rural settings by affording effective and early control of SARS-CoV-2 infection spread. We sought to assess the contribution of different COVID-19 testing procedures in rural Egypt. We conducted a prospective cohort study in a rural lab in Giza, Egypt. Approximately 223 individuals with potential SARS-CoV-2 infection were involved in the study during the pandemic peak in Giza, Egypt, from March 4 – May 30, 2021. Subjects were subjected to RT-PCR and rapid antigen testing, and the performance of each testing procedure was compared. Between March 4 – May 30, 2021, approximately 223 symptomatic individuals were included in this study. 190 patients (85.2%) were indicated as PCR positive for SARS-CoV-2, while 33 (14.8%) were PCR negative. In comparison, a rapid antigen test showed 178 out of 223 patients (79.8%) were indicated as positive, or 94% of the PCR-positive individuals. In Giza, a rural area of Egypt, RT-PCR had an optimal balance of sensitivity and specificity, however, the turnaround time was a limiting factor. Antigen testing, performed as a rapid point-of-care test, can play an effective role in rural outbreak control due to its ease of use and rapid results.

Early diagnosis by antigen test kit and early treatment by antiviral therapy: An ambulatory management strategy during COVID-19 crisis in Thailand

This study aimed to assess the clinical characteristics of patients who registered at the Siriraj Favipiravir Clinic and to share our experiences in this comparatively unique clinical setting. This retrospective study included patients who registered at the Siriraj Favipiravir Clinic during August 11, 2021 to September 14, 2021. Included adult patients were those with severe acute respiratory syndrome coronavirus 2 (coronavirus disease 2019 [COVID-19]) infection confirmed by antigen test kit (ATK) or real-time reverse transcription-polymerase chain reaction, no favipiravir contraindication, no prior COVID-19 treatment, and not receiving care from another medical facility. Demographic data and outcomes were collected and analyzed. Of the 1168 patients (mean age: 44.8 ± 16.4 years, 55.7% female) who registered at the clinic, 117 (10%) did not meet the treatment criteria, and 141 (12%) patients did not pick up their medication. One-third of patients had at least 1 symptom that indicated severe disease. Higher proportion of unvaccinated status (56.7% vs 47.5%, P = .005), higher proportion of persons with risk factors for disease progression (37.7% vs 31.3%, P = .028), and longer duration between the date of clinic registration and the date of positive diagnostic test (3 vs 2 days, P = .004) were significantly more commonly observed in the severe disease group compared to the nonsevere disease group. The duration between symptom onset and the date of clinic registration was significantly longer in the real-time reverse transcription-polymerase chain reaction group than in the ATK group (6 vs 4 days, P < .001). Most patients (90.0%) had completed favipiravir treatment regimen. The improvement and mortality rates were 86.7% and 1.2%, respectively. COVID-19 severity is associated with vaccination status, baseline risk factors, and timing between disease detection and treatment. The use of ATK influences patients to seek treatment significantly earlier in ambulatory setting. Our early diagnosis and antiviral treatment strategy yielded favorable results in an outpatient setting during a COVID-19 outbreak in Thailand.

Global Prevalence and Risk of Local Recurrence following Cryosurgery of Giant Cell Tumour of Bone: A Meta-Analysis

Simple Summary

Giant cell tumours are benign but locally aggressive and can potentially metastasise to the lungs. Reducing the risk of local recurrence while maintaining limb function and minimising adverse consequences is the best therapeutic strategy in treating giant cell tumours. Based on our observation through this meta-analysis, cryosurgery is one of the viable treatment options that can provide good oncologic and functional outcomes with minimal complication rates.

Abstract

The challenge in the surgical treatment of giant cell tumours of bone is the relatively high recurrence rate after curettage alone. The use of a local adjuvant following curettage, on the other hand, has lowered the rate of recurrence. This systematic review and meta-analysis aimed to investigate the prevalence and risk of local recurrence of giant cell tumours of the bone after cryosurgery and the subsequent complications. Web of Science, Scopus, ScienceDirect, PubMed, and Google Scholar were searched to identify articles published until 13 October 2021. A random-effects model was used to examine the pooled prevalence and risk ratio (RR) of local recurrence in patients with giant cell tumours after cryosurgery with 95% confidence intervals (CIs). This study was registered with PROSPERO (CRD42020211620). A total of 1376 articles were identified, of which 38 studies (n = 1373, 46.2% male) were included in the meta-analysis. Following cryosurgery, the pooled prevalence of local recurrence in giant cell tumours was estimated as 13.5% [95% CI: 9.3–17.8, I² = 63%], where European subjects exhibited the highest prevalence (24.2%). Compared to other local adjuvants. The RR of local recurrence following cryosurgery was 0.85 (95% CI: 0.63–1.17, I² = 15%), which was not statistically significant compared to other local adjuvants. We found 3.9% fracture, 4.0% infection, 2.1% nerve injury, and 1.5% skin necrosis as the common complications. Based on the sensitivity analyses, this study is robust and reliable. This meta-analysis estimated a low prevalence of local recurrence of giant cell tumours with low complications following cryosurgery. Thus, it can be one of the adjuvant options for treating giant cell tumours.

Clinical Performance of Rapid and Point-of-Care Antigen Tests for SARS-CoV-2 Variants of Concern: A Living Systematic Review and Meta-Analysis

Rapid antigen tests (RATs) for detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are widely used in the Coronavirus disease 2019 (COVID-19) pandemic caused by diverse variants. Information on the real-world performance of RATs for variants is urgently needed for decision makers. Systematic searches of the available literature and updates were conducted in PubMed, Ovid-MEDLINE, Ovid-EMBASE, CENTRAL, and KMBASE for articles evaluating the accuracy of instrument-free RATs for variants up until 14 March 2022. A bivariate random effects model was utilized to calculate pooled diagnostic values in comparison with real-time reverse transcription-polymerase chain reaction as the reference test. A total of 7562 samples from six studies were available for the meta-analysis. The overall pooled sensitivity and specificity of RATs for variants were 69.7% (95% confidence interval [CI] = 62.5% to 76.1%) and 100.0% (95% CI = 98.8% to 100.0%), respectively. When an additional 2179 samples from seven studies reporting sensitivities only were assessed, the pooled sensitivity dropped to 50.0% (95% CI = 44.0% to 55.0%). These findings suggest reassessment and monitoring of the diagnostic utility of RATs for variants, especially for the sensitivity aspect, to facilitate appropriate diagnosis and management of COVID-19 patients.

High Diagnostic Accuracy of a Novel Lateral Flow Assay for the Point-of-Care Detection of SARS-CoV-2

Highly accurate lateral flow immunochromatographic tests (LFTs) are an important public health tool to tackle the ongoing COVID-19 pandemic. The aim of this study was to assess the comparative diagnostic performance of the novel ND COVID-19 LFT under real-world conditions. A total of 400 nasopharyngeal swab specimens with a wide range of viral loads were tested in both reverse-transcription polymerase chain reaction and ND LFT. The overall sensitivity and specificity were 85% (95% CI: 76.7−90.7%) and 100% (95% CI: 98.7−100%), respectively. There was a clear association between the false-negative rate and sample viral load: the sensitivity parameters for specimens with cycle threshold values of <25 (>3.95 × 106 copies/mL) and ≥30 (≤1.29 × 105 copies/mL) were 100% and 50%, respectively. The performance was maximized in testing samples with viral loads ≥1.29 × 105 copies/mL. These findings suggest that the ND LFT is sufficiently accurate and useful for mass population screening programs, especially in high-prevalence and resource-constrained settings or during periods when the epidemic curve is rising. Other public health implications were also discussed.

Performance of Antigen Detection Tests for SARS-CoV-2: A Systematic Review and Meta-Analysis

Coronavirus disease 2019 (COVID-19) initiated global health care challenges such as the necessity for new diagnostic tests. Diagnosis by real-time PCR remains the gold-standard method, yet economical and technical issues prohibit its use in points of care (POC) or for repetitive tests in populations. A lot of effort has been exerted in developing, using, and validating antigen-based tests (ATs). Since individual studies focus on few methodological aspects of ATs, a comparison of different tests is needed. Herein, we perform a systematic review and meta-analysis of data from articles in PubMed, medRxiv and bioRxiv. The bivariate method for meta-analysis of diagnostic tests pooling sensitivities and specificities was used. Most of the AT types for SARS-CoV-2 were lateral flow immunoassays (LFIA), fluorescence immunoassays (FIA), and chemiluminescence enzyme immunoassays (CLEIA). We identified 235 articles containing data from 220,049 individuals. All ATs using nasopharyngeal samples show better performance than those with throat saliva (72% compared to 40%). Moreover, the rapid methods LFIA and FIA show about 10% lower sensitivity compared to the laboratory-based CLEIA method (72% compared to 82%). In addition, rapid ATs show higher sensitivity in symptomatic patients compared to asymptomatic patients, suggesting that viral load is a crucial parameter for ATs performed in POCs. Finally, all methods perform with very high specificity, reaching around 99%. LFIA tests, though with moderate sensitivity, appear as the most attractive method for use in POCs and for performing seroprevalence studies.

Accuracy of Rapid Antigen vs Reverse Transcriptase-Polymerase Chain Reaction Testing for SARS-CoV-2 Infection in College Athletes During Prevalence of the Omicron Variant

This case series evaluates the performance of rapid antigen tests in detecting SARS-CoV-2 infection in college athletes during prevalence of a dominant Omicron variant.

Clinical Accuracy of Instrument-Read SARS-CoV-2 Antigen Rapid Diagnostic Tests (Ag-IRRDTs)

This systematic review (PROSPERO registration number: CRD42021282476) aims to collect and analyse current evidence on real-world performance based on clinical accuracy of instrument-read rapid antigen diagnostic tests (Ag-IRRDTs) for SARS-CoV-2 identification. We used PRISMA Checklist and searched databases (PubMed, Web of Science Core Collection and FIND) for publications evaluating the accuracy of SARS-CoV-2 Ag-IRRDTs as of 30 September 2021, and included 40 independent clinical studies resulting in 48 Ag-IRRDT datasets with 137,770 samples. Across all datasets, pooled Ag-IRRDT sensitivity was 67.1% (95% CI: 65.9%-68.3%) and specificity was 99.4% with a tight CI. Pooled sensitivity and specificity of SARS-CoV-2 Ag-IRRDTs did not demonstrate a significant superiority over SARS-CoV-2 rapid antigen tests which do not require a reader instrument, even in the case where surveillance and screening datasets were excluded from the analysis. Nevertheless, they provide connectivity advantages and remove operator interface (in results-reading) issues. The lower sensitivity of certain brands of Ag-IRRDTs can be overcome in high prevalence areas with high frequency of testing. New SARS-CoV-2 variants are major concern for current and future diagnostic performance of these tests.

Six-month longitudinal tracking of arterial stiffness and blood pressure in young adults following SARS-CoV-2 infection

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can increase arterial stiffness 3–4 wk following infection, even among young, healthy adults. However, the long-term impacts of SARS-CoV-2 infection on cardiovascular health and the duration of recovery remain unknown. The purpose of this study was to elucidate potential long-lasting effects of SARS-CoV-2 infection on markers of arterial stiffness among young adults during the 6 mo following infection. Assessments were performed at months 1, 2, 3, 4, and ∼6 following SARS-CoV-2 infection. Doppler ultrasound was used to measure carotid-femoral pulse wave velocity (cfPWV) and carotid stiffness, and arterial tonometry was used to measure central blood pressures and aortic augmentation index at a heart rate of 75 beats·min⁻¹ (AIx@HR75). Vascular (VCAM-1) and intracellular (ICAM-1) adhesion molecules were analyzed as circulating markers of arterial stiffness. From months 1–6, a significant reduction in cfPWV was observed (month 1: 5.70 ± 0.73 m·s⁻¹; month 6: 4.88 ± 0.65 m·s⁻¹; P < 0.05) without any change in carotid stiffness measures. Reductions in systolic blood pressure (month 1: 123 ± 8 mmHg; month 6: 112 ± 11 mmHg) and mean arterial pressure (MAP; month 1: 97 ± 6 mmHg; month 6: 86 ± 7 mmHg) were observed (P < 0.05), although AIx@HR75 did not change over time. The month 1–6 change in cfPWV and MAP were correlated (r = 0.894; P < 0.001). A reduction in VCAM-1 was observed at month 3 compared with month 1 (month 1: 5,575 ± 2,242 pg·mL⁻¹; month 3: 4,636 ± 1,621 pg·mL⁻¹; P < 0.05) without a change in ICAM-1. A reduction in cfPWV was related with MAP, and some indicators of arterial stiffness remain elevated for several months following SARS-CoV-2 infection, possibly contributing to prolonged recovery and increased cardiovascular health risks.

NEW & NOTEWORTHY We sought to investigate potential long-lasting effects of SARS-CoV-2 infection on markers of arterial stiffness among young adults for 6 mo following infection. Carotid femoral pulse wave velocity was significantly reduced while carotid stiffness measures remained unaltered over the 6-mo period. These findings suggest several months of recovery from infection may be necessary for young adults to improve various markers of arterial stiffness, possibly contributing to cardiovascular health and recovery among those infected with SARS-CoV-2.

Microfluidics Technology in SARS-CoV-2 Diagnosis and Beyond: A Systematic Review

With the progression of the COVID-19 pandemic, new technologies are being implemented for more rapid, scalable, and sensitive diagnostics. The implementation of microfluidic techniques and their amalgamation with different detection techniques has led to innovative diagnostics kits to detect SARS-CoV-2 antibodies, antigens, and nucleic acids. In this review, we explore the different microfluidic-based diagnostics kits and how their amalgamation with the various detection techniques has spearheaded their availability throughout the world. Three other online databases, PubMed, ScienceDirect, and Google Scholar, were referred for articles. One thousand one hundred sixty-four articles were determined with the search algorithm of microfluidics followed by diagnostics and SARS-CoV-2. We found that most of the materials used to produce microfluidics devices were the polymer materials such as PDMS, PMMA, and others. Centrifugal force is the most commonly used fluid manipulation technique, followed by electrochemical pumping, capillary action, and isotachophoresis. The implementation of the detection technique varied. In the case of antibody detection, spectrometer-based detection was most common, followed by fluorescence-based as well as colorimetry-based. In contrast, antigen detection implemented electrochemical-based detection followed by fluorescence-based detection, and spectrometer-based detection were most common. Finally, nucleic acid detection exclusively implements fluorescence-based detection with a few colorimetry-based detections. It has been further observed that the sensitivity and specificity of most devices varied with implementing the detection-based technique alongside the fluid manipulation technique. Most microfluidics devices are simple and incorporate the detection-based system within the device. This simplifies the deployment of such devices in a wide range of environments. They can play a significant role in increasing the rate of infection detection and facilitating better health services.

Identification of contagious SARS-CoV-2 infected individuals by Roche's Rapid Antigen Test

OBJECTIVES

Rapid antigen tests (RAT) can provide valuable information on the presence or absence SARS-CoV-2 within 15 min without the need of a laboratory. The analytical and diagnostic characteristics of available RATs has led to the question whether they can safely distinguish between infectious and non-infectious patients in an acute care setting.

METHODS

Three nasopharyngeal swabs for the analysis by RAT, reverse transcriptase real time polymerase chain reaction (RT-qPCR), and a cell culture based infection assay were collected from 67 patients that presented to the emergency department of the University Hospital of Graz (Austria). The first swab was used for on-site RAT testing in the emergency department using the Roche SARS-CoV-2 RAT. The second swab was sent to the central laboratory of the hospital for RT-qPCR with two independent methods (Cepheid Xpert® Xpress SARS-CoV-2 assay and Roche Cobas SARS-CoV-2 Test) and repeat RAT testing using the same commercial test. With the third swab a cell culture-based infection assay was performed.

RESULTS

The RATs performed from independent samples showed substantial agreement (Cohen's-kappa: 0.73, p<0.001). All patients with a positive RAT had positive RT-qPCR with cycle threshold (ct) values <25. Fifteen out of 55 RAT-negative samples were RT-qPCR positive with ct values between 25 and 40. The inoculation of cell cultures with RT-qPCR negative swabs and RT-qPCR positive swabs with ct values >25 did not induce cytopathic effects that were related to SARS-CoV-2. The infection assays from four RAT-negative patients showed cytopathic effects that were induced by other pathogens.

CONCLUSIONS

The SARS-CoV-2 RAT from Roche Diagnostics is a valuable tool for managing symptomatic patients. RAT-negative patients may be regarded as non-contagious.