Graphene-Based Electrochemical Nano-Biosensors for Detection of SARS-CoV-2

COVID-19, a viral respiratory illness, is caused by Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2), which was first identified in Wuhan, China, in 2019 and rapidly spread worldwide. Testing and isolation were essential to control the virus's transmission due to the severity of the disease. In this context, there is a global interest in the feasibility of employing nano-biosensors, especially those using graphene as a key material, for the real-time detection of the virus. The exceptional properties of graphene and the outstanding performance of nano-biosensors in identifying various viruses prompted a feasibility check on this technology. This paper focuses on the recent advances in using graphene-based electrochemical biosensors for sensing the SARS-CoV-2 virus. Specifically, it reviews various types of electrochemical biosensors, including amperometric, potentiometric, and impedimetric biosensors, and discusses the current challenges associated with biosensors for SARS-CoV-2 detection. The conclusion of this review discusses future directions in the field of electrochemical biosensors for SARS-CoV-2 detection, underscoring the importance of continued research and development in this domain.

Rapid antigen test in diagnosis of SARS-COV-2 in a specialized care facility Urology and Nephrology Center–Mansoura University-Egypt

Background: Polymerase chain reaction (PCR) is the benchmark in diagnosing of corona virus disease. It takes at least 4 hours. Multiple studies reported that rapid antigen test could be used. Their role in diagnosing corona virus disease 2019 (COVID-19) is questionable. This study was conducted to assess the accuracy of rapid antigen test in Urology and Nephrology Center Mansoura University, Egypt. Methods: COVID-19 rapid ag test was evaluated in comparison to real time PCR as a gold standard in diagnosis of COVID-19 infection in employees and patients with respiratory symptoms in specialized care facility Urology and Nephrology Center of Mansoura University from March 2020 till August 2021. Complete blood picture and non-contrast computerized tomography (CT) was done. Results: Eight hundred and eighty-four (884) individuals (median age 36 years) were included in this study: 478 healthcare workers, 217 non-healthcare workers, and 189 patients. PCR was positive in 569 samples and negative in 315. Out of 315 negative PCR samples, 8 were positive by rapid antigen test with a specificity of 97.4%. Conclusion: Rapid antigen tests in comparison to PCR test have a good accuracy in diagnosis in of COVID-19 infection and can be used during pandemics in low-resource areas. © 2020 The author (s). Published by Zagazig University.

Screening Hesitancy of a Universal Voluntary-based Rapid Antigen Test for coronavirus disease 2019 (COVID-19) During Omicron Wave in Hong Kong.

BACKGROUND: The Hong Kong government distributed rapid antigen test (RAT) kits to households across the city and called for a universal voluntary testing exercise for three consecutive days during the Omicron wave to identify infected persons early for quarantine and disrupt transmission chains in the community. We conducted a survey to evaluate the participation rates and explore the determinants of voluntary RAT adoption and hesitancy. METHODS: This cross-sectional survey was conducted through computer-assisted telephone interviews from 19 May to 16 June 2022 using an overlapping dual-frame telephone number sampling design. Information on willingness to adopt voluntary RAT, four themes of personal qualities, attitudes toward the government's health policies, incentives to motivate RAT adoption, and personal sociodemographic factors were collected. Logistic regression analysis was used to examine the factors associated with RAT adoption. RESULTS: Of the 1010 participants, 490 successfully responded to the fixed-line and 520 to the mobile phone survey, with response rates of 1.42% and 1.63% and screen hesitancy rates of 36.1% and 39.3%, respectively. Participants of adoption RAT were those aged 30-49 years, with high perceived COVID-19 infection severity, ≥ 3 doses of COVID-19 vaccination, and more agreement with the health policies on material resources and quarantine orders. Individuals who were less risk seeking and more altruistic reported a higher adoption of voluntary RAT. CONCLUSIONS: Understanding the willingness to participate in a voluntary universal testing programme might shed light on effective ways to minimise screening hesitancy in future public health strategies and campaigns.

Utilization of rapid antigen tests for screening SARS-CoV-2 prior to dental treatment.

Potential aerosols containing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral particles can be generated during dental treatment. Hence, patient triage is essential to prevent the spread of SARS-CoV-2 in dental clinical settings. The present study described the use of rapid antigen tests for SARS-CoV-2 screening prior to dental treatment in an academic dental clinical setting in Thailand during the pandemic. The opinions of dental personnel toward the use of rapid antigen test screening prior to dental treatment were also assessed. From August 25 to October 3, 2021, dental patients who were expected to receive aerosols generating dental procedures were requested to screen for SARS-CoV-2 using a rapid antigen test before their treatment. A total of 7,618 cases completed the screening process. The average was 212 cases per day. Only five patients (0.07%) were positive for SARS-CoV-2 in the rapid antigen screening tests. All positive cases exhibited mild symptoms. For the questionnaire study, experienced dental personnel frequently and consistently agreed with the use of the rapid antigen test for SARS-CoV-2 screening, which made them feel safer during their patient treatment. However, implementing rapid antigen tests for SARS-CoV-2 may increase the total time spent on a dental appointment. In conclusion, a rapid antigen test could detect the infected individual prior to dental treatment. However, the specificity of rapid antigen tests for SARS-CoV-2 must be taken into account for consideration as a screening process before dental treatment. The enhanced infection control protocols in dental treatment must be consistently implemented.

Evaluation of "Test to Return" after COVID-19 Diagnosis in a Massachusetts Public School District.

BACKGROUND: Per Centers for Disease Control and Prevention guidance, students with COVID-19 may end isolation after 5 days if symptoms are improving; some individuals may still be contagious. Rapid antigen testing identifies possibly infectious virus. We report on a test-to-return (TTR) program in a Massachusetts school district to inform policy decisions about return to school after COVID-19. METHODS: During the 2021-2022 Omicron BA.1 surge, students with COVID-19 could return on day 6-10 if they met symptom criteria and had a negative rapid test; students with positive rapid tests and those who declined TTR remained isolated until day 11. TTR positivity rates were compared by grade level, vaccination status, symptom status, and day of infection. RESULTS: 31.4% of students had a positive TTR rapid test; there were no differences by grade or vaccination status. Ever-symptomatic students were more likely to have a positive rapid test (75/174 [43.1%] vs 18/104 [17.3%]). For ever-symptomatic students, TTR positivity decreased by day of infection. CONCLUSIONS: A substantial proportion of students may still be contagious 6 days after onset of COVID-19 infection. TTR programs may increase or reduce missed school days, depending on when return is otherwise allowed (day 6 or 11). The impact of TTR programs on school-associated transmission remains unknown.

Clinical features of COVID-19 rapid antigen test exposures reported by an Australian poisons information centre: a prospective study.

INTRODUCTION: Coronavirus disease COVID-19 rapid antigen tests are a useful tool in detecting infection, and their use has increased in many countries since they became commercially available in late 2021. Some rapid antigen tests contain sodium azide, which can be toxic in small doses. This study aimed to describe the clinical characteristics of exposures to COVID-19 rapid antigen tests. METHODS: This is a prospective study conducted by the New South Wales Poisons Information Centre. From 22 January 2022 to 31 August 2022, rapid antigen test exposures were followed up to obtain outcome information. Data collected included: brand/ingredients, exposure route, demographics, symptoms, and disposition. RESULTS: We recorded 218 exposures in the seven-month study period. Complete follow-up information was available in 75% (n = 164). There were 53 exposures to sodium azide-containing products (35 with follow-up data) and 165 to non-sodium azide-containing products and unknown ingredient exposures (129 with follow-up data). Overall, unintentional exposures predominated (n = 182), and 151 were ingestions. The vast majority (>90%) did not develop symptoms, and all symptoms that developed were mild. Most cases (95%, n = 208) did not require referral to a healthcare facility. CONCLUSIONS: In this prospective series, few patients developed symptoms, regardless of the sodium azide content, likely due to low concentration and low volume within the test kits. However, ongoing toxicovigilance is warranted.

Efficiency analysis of rapid antigen test based SARS-CoV-2 in hospital contact tracing and screening regime: test characteristics and cost effectiveness.

In the context of the current SARS-CoV-2 pandemic, reliable and cost-efficient screening and testing strategies are crucial to prevent disease transmission and reduce socioeconomic losses. To assess the efficiency of a rapid antigen test (RAT)-based SARS-CoV-2 contact-tracing and screening regime, we conducted a retrospective analysis of RAT and polymerase chain reaction (PCR) test data over a 1-year period, assessed test characteristics and estimated cost-effectiveness. The RAT had a sensitivity of 70.2% overall and 89.3% for people with a high risk of infectivity. We estimated inpatient treatment and quarantined healthcare worker costs of over € 5860.83, whereas the cost of identifying one SARS-CoV-2 positive person by RAT for our patient cohort was € 1210.75. In contrast, the estimated respective PCR cost was € 5043.32. Therefore, a RAT-based contract tracing and screening regime may be an efficient and cost-effective way to contribute to the early identification and prevention of SARS-CoV-2 transmission.

Evaluation of the new 2.0 version of the Roche SARS-CoV-2 Rapid Antigen Test.

We evaluated the new 2.0 version of the Roche Diagnostics SARS-CoV-2 Rapid Antigen Test (RAT 2.0) for the detection of SARS-CoV-2. Our evaluation material comprised of nasopharyngeal samples of 140 persons positive for SARS-CoV-2 nucleic acid amplification test (NAAT) and of 100 persons negative for SARS-CoV-2 NAAT. The sensitivity limit of the RAT 2.0 was further estimated with the additional selected samples of 27 persons with high NAAT cycle threshold (Ct) value representing low viral load. For the detection of possible cross-reactions in the RAT 2.0, routine respiratory samples positive for influenza A (N = 5), respiratory syncytial virus (RSV) (N = 4), or combined RSV and human coronavirus OC43 (N = 1) were included in the study material. The overall sensitivity of the RAT 2.0 was 92.1% and specificity 100%. When evaluating the samples with NAAT Ct value ≤ 30, the sensitivity was 97.0%. All samples for cross-reactivity testing containing other viruses instead of SARS-CoV-2 remained negative in RAT 2.0. According to our findings, this RAT 2.0 offers a reliable tool for the diagnostics of acute COVID-19 in this pandemic environment.

Testing Strategy of Covid-19: A Mechanistic Approach

The deadliness associated with the COVID-19 disease caused by the SARS-CoV-2 virus plunged the entire global community into the worst times of this century. It was globally realized that a timely diagnosis, effective treatment, and prevention were the key factors in its management. Responding to the emergent scenario, sequencing of the genome of this virus was performed and shared with the scientific community in the nick of time. Thereafter, diverse sets of test kits to detect the SARS-CoV-2 and to detect the antibodies in the patients of the COVID-19 were developed at the war scale. It was indeed a war but with a microscopic spiky package of 50–200 nanometres in diameter having a genome of about 29.9 kb encoding deadly tools in its arsenal. For the reason, patients of the COVID-19 exhibit diverse symptoms from mild influenza-like to potentially fatal ones that overlap with other respiratory diseases, only efficient testing was essential during the early stages of infection to identify COVID-19 patients among others. The diverse test kits designed exclusively for rapid and accurate outcomes proved instrumental in identifying individuals among asymptomatics, presymptomatics, and symptomatics. The test kits have also been playing an appreciable role in identifying communities with hot spots to facilitate proper management. To meet the demand of higher throughput and simplification of the testing process, novel ways were devised that did not otherwise allow the testing spree to get hit with pandemic supply bottlenecks. Mechanistic models have played an essential role in shaping public health policy. The regulatory agencies, both at the world health and the regional public health levels, shared the knowledge and experience on the test kits that helped in the development and improvement in the testing capability and efficiency of the testing infrastructure. The information about the emergence of variants of the SARS-CoV-2 happening due to intrinsic behavior of the viral genomes drew attention of the test kit developers, regulatory agencies, and end-users to be vigilant over the test outcomes. Offering a mechanistic approach, in this chapter, testing strategies for the detection of SARS-CoV-2 virus and COVID-19 disease are delineated. © The Author(s), under exclusive licence to Springer Nature Singapore Pte Ltd. 2021.

Rapid Diagnostics in Infection Prevention

There are several relevant pathogens in healthcare today that are easily transmissible among populations and are associated with significant morbidity and mortality. In order to decrease transmission, it is important to identify infected patients quickly so that infection prevention techniques can be employed. Rapid diagnostic tests assist with this as they often produce results 24-48 h faster than traditional culture and sensitivity methods. This chapter discusses the benefits and limitations of rapid diagnostic tests overall, as well as considerations for rapid diagnostics for carbapenem-resistant Enterobacteriaceae (CRE), methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus spp. (VRE), Clostridioides difficile, Candida auris, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and influenza. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2022.

Sensitivity of rapid antigen tests for Omicron subvariants of SARS-CoV-2.

Diagnosis by rapid antigen tests (RATs) is useful for early initiation of antiviral treatment. Because RATs are easy to use, they can be adapted for self-testing. Several kinds of RATs approved for such use by the Japanese regulatory authority are available from drug stores and websites. Most RATs for COVID-19 are based on antibody detection of the SARS-CoV-2 N protein. Since Omicron and its subvariants have accumulated several amino acid substitutions in the N protein, such amino acid changes might affect the sensitivity of RATs. Here, we investigated the sensitivity of seven RATs available in Japan, six of which are approved for public use and one of which is approved for clinical use, for the detection of BA.5, BA.2.75, BF.7, XBB.1, and BQ.1.1, as well as the delta variant (B.1.627.2). All tested RATs detected the delta variant with a detection level between 7500 and 75 000 pfu per test, and all tested RATs showed similar sensitivity to the Omicron variant and its subvariants (BA.5, BA.2.75, BF.7, XBB.1, and BQ.1.1). Human saliva did not reduce the sensitivity of the RATs tested. Espline SARS-CoV-2 N showed the highest sensitivity followed by Inspecter KOWA SARS-CoV-2 and V Trust SARS-CoV-2 Ag. Since the RATs failed to detect low levels of infectious virus, individuals whose specimens contained less infectious virus than the detection limit would be considered negative. Therefore, it is important to note that RATs may miss individuals shedding low levels of infectious virus.

SARS-CoV-2 antigen detection by saliva; an alternative to nasopharyngeal specimen: A cross-sectional study.

Background and Aims: Saliva samples are less invasive and more convenient for patients than naso- and/or oropharynx swabs (NOS). However, there is no US Food and Drug Administration-approved severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) rapid antigen test kit, which can be useful in a prolonged pandemic to reduce transmission by allowing suspected individuals to self-sampling. We evaluated the performances of High sensitive AQ+ Rapid SARS-CoV-2 Antigen Test (AQ+ kit) using nasopharyngeal swabs (NPs) and saliva specimens from the same patients in laboratory conditions. Methods: The real-time reverse transcription-polymerase chain reaction (rRT-PCR) test result was used for screening the inrolled individuals and compared as the gold standard. NP and saliva samples were collected from 100 rRT-PCR positives and 100 negative individuals and tested with an AQ+ kit. Results: The AQ+ kit showed good performances in both NP and saliva samples with an overall accuracy of 98.5% and 94.0%, and sensitivity of 97.0% and 88.0%, respectively. In both cases, specificity was 100%. AQ+ kit performance with saliva was in the range of the World Health Organization recommended value. Conclusion: xOur findings indicate that the saliva specimen can be used as an alternative and less invasive to NPs for quick and reliable SARS-CoV-2 antigen detection.

Diagnostics for Viral Pathogens in Veterinary Diagnostic Laboratories.

Laboratory testing is one part of clinical diagnosis, and quick and reliable testing results provide important data to support treatment decision and develop control strategies. Clinical viral testing has been shifting from traditional virus isolation and electron microscopy to molecular polymerase chain reaction and point-of-care antigen tests. This shift in diagnostic methodology also means change from looking for infectious virions or viral particles to hunting viral antigens and genomes. With technological development, it is predicted that metagenomic sequencing will be commonly used in veterinary clinical diagnosis for unveiling the whole picture of microbes involved in diseases in the future.

Clinical evaluation of anterior nasal cavity swab specimens by a rapid antigen test using a GLINE-2019-nCoV Ag Kit to diagnose COVID-19.

The promising diagnostic performance of rapid antigen tests (RATs) using non-invasive anterior nasal (AN) swab specimens to diagnose COVID-19 has been reported. A large number of RATs are commercially available; however, the careful assessment of RATs is essential prior to their implementation in clinical practice. We evaluated the clinical performance of the GLINE-2019-nCoV Ag Kit as a RAT using AN swabs in a prospective, blinded study. Adult patients who visited outpatient departments and received SARS-CoV-2 tests between August 16 and September 8, 2022, were eligible for this study. Patients who were aged under 18 years and patients without appropriate specimens were excluded. Two sets of AN and nasopharyngeal (NP) swabs were collected from all patients. Each set of specimens was tested by the RAT and quantitative reverse-transcription polymerase chain reaction (RT-qPCR). Of the 138 recruited patients, 84 were positive and 54 were negative by RT-qPCR using NP swabs. The positive agreement rate between RT-qPCR using NP swabs and RAT using AN swabs was 78.6% (95% confidence interval [CI], 68.3%-86.8%), the negative agreement rate was 98.1% (95% CI, 90.1%-99.9%), and the overall agreement rate was 86.2% (95% CI, 79.3%-91.5%), with a κ coefficient of 0.73. The positive agreement rate in the early phase (≤3 days from symptom onset) was >80%, but this fell to 50% in the late phase (≥4 days). This study demonstrates that the GLINE-2019-nCoV Ag Kit using AN swabs has good clinical performance and might be a reliable alternative method for diagnosing COVID-19.

COVID-19 testing protocols to guide duration of isolation: a cost-effectiveness analysis.

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.

A Reagent and Virus Benchmarking Panel for a Uniform Analytical Performance Assessment of N Antigen-Based Diagnostic Tests for COVID-19.

Rapid diagnostic tests (RDTs) that detect antigen indicative of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection can help in making quick health care decisions and regularly monitoring groups at risk of infection. With many RDT products entering the market, it is important to rapidly evaluate their relative performance. Comparison of clinical evaluation study results is challenged by protocol design variations and study populations. Laboratory assays were developed to quantify nucleocapsid (N) and spike (S) SARS-CoV-2 antigens. Quantification of the two antigens in nasal eluates confirmed higher abundance of N than S antigen. The median concentration of N antigen was 10 times greater than S per genome equivalent. The N antigen assay was used in combination with quantitative reverse transcription (RT)-PCR to qualify a panel composed of recombinant antigens, inactivated virus, and clinical specimen pools. This benchmarking panel was applied to evaluate the analytical performance of the SD Biosensor Standard Q COVID-19 antigen (Ag) test, Abbott Panbio COVID-19 Ag rapid test, Abbott BinaxNOW COVID-19 Ag test, and the LumiraDx SARS-CoV-2 Ag test. The four tests displayed different sensitivities toward the different panel members, but all performed best with the clinical specimen pool. The concentration for a 90% probability of detection across the four tests ranged from 21 to 102 pg/mL of N antigen in the extracted sample. Benchmarking panels provide a quick way to verify the baseline performance of a diagnostic and enable direct comparisons between diagnostic tests. IMPORTANCE This study reports the results for severe acute respiratory syndrome coronavirus-2 (SARS-COV-2) nucleocapsid (N) and spike (S) antigen quantification assays and their performance against clinical reverse transcription (RT)-PCR results, thus describing an open-access quantification method for two important SARS-CoV-2 protein analytes. Characterized N antigen panels were used to evaluate the limits of detection of four different rapid tests for SARS-CoV-2 against multiple sources of nucleocapsid antigen, demonstrating proof-of-concept materials and methodology to evaluate SARS-CoV-2 rapid antigen detection tests. Quantification of N antigen was used to characterize the relationship between viral count and antigen concentration among clinical samples and panel members of both clinical sample and viral culture origin. This contributes to a deeper understanding of protein antigen and molecular analytes and presents analytical methods complementary to clinical evaluation for characterizing the performance of both laboratory-based and point-of-care rapid diagnostics for SARS-CoV-2.

Expert Consensus on Rapid SARS-CoV-2 Antigen Testing.

The epidemic of the highly contagious, long lasting and widely popular coronavirus disease 2019 (COVID-19) has imposed a huge burden to the global public health. As one of the key methods for early diagnosis of COVID-19 infection, rapid acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigen testing has been gradually applied in China. To address concerns raised by both health care workers and the public, based on the latest research and clinical practices, the Sub-committee of the Clinical Microbiology Laboratory of the Chinese Hospital Association proposed"Expert Consensus on Rapid SARS-CoV-2 Antigen Testing(2022)". The consensus panel is composed of experts from multiple disciplines, including laboratory medicine, clinical medicine, infection control, public health, research and development of in vitro diagnostic products. The consensus describes its principle, technological characteristics, results interpretation and, disposal recommendations, and analyzes the strategies and matters needing attention in different application scenarios. We expect the consensus to help correct understanding and application of rapid SARS-CoV-2 antigen testing in the diagnosis, treatment, prevention, and control of COVID-19.Copyright © 2022, Peking Union Medical College Hospital. All rights reserved.

REDACS: Regional emergency-driven adaptive cluster sampling for effective COVID-19 management

As COVID-19 is spreading, national agencies need to monitor and track several metrics. Since we do not have perfect testing programs on the hand, one needs to develop an advanced sampling strategies for prevalence study, control and management. Here we introduce REDACS: Regional emergency-driven adaptive cluster sampling for effective COVID-19 management and control and justify its usage for COVID-19. We show its advantages over classical massive individual testing sampling plans. We also point out how regional and spatial heterogeneity underlines proper sampling. Fundamental importance of adaptive control parameters from emergency health stations and medical frontline is outlined. Since the Northern hemisphere entered Autumn and Winter season (this paper was originally submitted in November 2020), practical illustration from spatial heterogeneity of Chile (Southern hemisphere, which already experienced COVID-19 winter outbreak peak) is underlying the importance of proper regional heterogeneity of sampling plan. We explain the regional heterogeneity by microbiological backgrounds and link it to behavior of Lyapunov exponents. We also discuss screening by antigen tests from the perspective of "on the fly" biomarker validation, i.e., during the screening. [ FROM AUTHOR] Copyright of Stochastic Analysis & Applications is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)

Rapid Detection of Sars Cov-2 Infection in Comparision with Rt-Pcr in Tertiary Care Hospital

Objectives: The goal of the present study was to assess the SARS-CoV-2 antigen detection test's performance features and compare them to the real-time reverse transcription polymerase chain reaction (RT-PCR) test, the gold standard test for the diagnosis of COVID-19 cases. Method(s): From October 2020 to May 2021, patients attending the OPD, including those undergoing surgery, at a Tertiary Care Teaching Hospital in Telangana provided 1000 respiratory samples, primarily nasopharyngeal swabs. A skilled technician had collected two nasopharyngeal swabs from each person in a COVID sample collection room while wearing personal protective equipment and following strict infection control procedures. One swab was used for the rapid antigen test given by the standard Q COVID-19 Ag test kit and placed into the extraction buffer tube. Second swab was kept in the viral transport medium and used for AllplexTM 2019-nCoV Assay (Seegene, Korea), which targets envelope gene (E), and RNA dependent RNA polymerase (RdRp) and nucleocapsid (N) genes of SARS CoV-2, was used for SARS-CoV-2 RNA detection according to the manufacturer's instructions. Result(s): Out of 1000 samples tested for COVID-19, 623 (63.7%) were males and 377 (36.3%) were females. Out of 1000 samples, 347 samples were RT-PCR positive and 653 were RT-PCR negative. Out of 347 RT-PCR samples positive, 341 were Rapid antigen test positive samples and six were negative. Overall sensitivity and specificity are 98.27% and 99.85%, respectively. Conclusion(s): The real-time RT-PCR assay's sensitivity and specificity were comparable to those of the rapid assay for SARS-CoV-2 antigen detection. It can be utilized for contact tracing measures to control the COVID-19 pandemic in places such as border crossings, airports, interregional bus and train stations, and mass testing campaigns needing quick findings. This is especially true in areas with a high prevalence of the disease.Copyright © 2023 The Authors. Published by Innovare Academic Sciences Pvt Ltd.

Factors affecting the sensitivity of quantitative severe acute respiratory syndrome coronavirus 2 antigen test.

INTRODUCTION: The accuracy of nucleic acid amplification tests (NAATs) is affected by various factors; however, studies examining the factors affecting the accuracy of quantitative severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigen test (QAT) are limited. METHODS: A total of 347 nasopharyngeal samples were collected from patients with coronavirus disease 2019 (COVID-19), and the date of onset was obtained from the electronic medical records. The SARS-CoV-2 antigen level was measured using Lumipulse Presto SARS-CoV-2 Ag (Presto), while NAAT was performed using the Ampdirect 2019-nCoV Detection Kit. RESULTS: Presto had a sensitivity rate of 95.1% (95% confidence interval: 92.8-97.4) in detecting the SARS-CoV-2 antigen in 347 samples. The number of days from symptom onset to sample collection was negatively correlated with the amount of antigen (r = -0.515) and sensitivity of Presto (r = -0.711). The patients' age was lower in the Presto-negative samples (median age, 39 years) compared with that in the Presto-positive samples (median age, 53 years; p < 0.01). A significant positive correlation was observed between age (excluding teenagers) and Presto sensitivity (r = 0.764). Meanwhile, no association was found between the mutant strain, sex, and Presto results. CONCLUSION: Presto is useful for the accurate diagnosis of COVID-19 owing to its high sensitivity when the number of days from symptom onset to sample collection is within 12 days. Furthermore, age may affect the results of Presto, and this tool has a relatively low sensitivity in younger patients.