Sensitivity Of Rapid Antigen Test Research Articles

Sensitivity of rapid antigen tests against SARS-CoV-2 Omicron and Delta variants.

Rapid antigen tests (RATs) have become an invaluable tool for combating the COVID-19 pandemic. However, concerns have been raised regarding the ability of existing RATs to effectively detect emerging SARS-CoV-2 variants. We compared the performance of 10 commercially available, emergency use authorized RATs against the Delta and Omicron SARS-CoV-2 variants using both individual patient and serially diluted pooled clinical samples. The RATs exhibited lower sensitivity for Omicron samples when using PCR cycle threshold (CT) value (a rough proxy for RNA concentration) as the comparator. Interestingly, however, they exhibited similar sensitivity for Omicron and Delta samples when using quantitative antigen concentration as the comparator. We further found that the Omicron samples had lower ratios of antigen to RNA, which offers a potential explanation for the apparent lower sensitivity of RATs for that variant when using C T value as a reference. Our findings underscore the complexity in assessing RAT performance against emerging variants and highlight the need for ongoing evaluation in the face of changing population immunity and virus evolution.

Sensitivity of rapid antigen tests for COVID-19 during the Omicron variant outbreak among players and staff members of the Japan Professional Football League and clubs: a retrospective observational study

ObjectivesRapid antigen tests have been used to prevent the spread of the COVID-19; however, there have been concerns about their decreased sensitivity to the Omicron variant. In this study, we...

Efficacy Of PanbioTM Covid-19 Ag Rapid Test In Sars-Cov-2 Detection: Comparison With RT-PCR Test.

Evidence on performance of Rapid Antigen Detection Tests to recognize SARS-CoV-2 symptomatic patients in our context is limited. This study was aimed to evaluate Panbio™ COVID-19 Ag Rapid Test Device (Abbott Diagnostics, Jena, Germany) in identifying SARS-CoV-2 infection in comparison with RT-PCR test. This cross-sectional validation study was carried out at Margalla Hospital, Taxila from October, 2020 to March, 2021. Three hundred and eighty-two participants of both gender and all ages, symptomatic for 3-4 days were included in this study. For each participant, two nasopharyngeal swabs were collected by trained lab technicians according to SOPs, one for Rapid Antigen Test and other for RT-PCR.Covid-19 antibodies were checked 4-6 weeks after symptoms among 77 randomly selected participants to further evaluate the performance of Rapid Antigen Test. Data was analyzed using SPSS-26. The mean age of the participants was 43.1 years (SD=15.9). More than half of participants were males (n=213%=55.8) and 169 (44.2%) were females. Sensitivity of Rapid Antigen Test was calculated to be 94.3%, whereas the specificity was 39.7%. Out of 34 RT-PCR negatives that were initially detected positive on Rapid Antigen Test, 33 demonstrated presence of COVID-19 antibodies. Panbio™ COVID-19 Ag Rapid Test was found to have 93.4% overall sensitivity and relatively low overall specificity (37.9%). Rapid antigen testing using Panbio™ COVID-19 Ag Rapid Test Device can be effectively used to scale up mass testing to interrupt transmissibility of COVID-19 infection by generating quick result.

Decreased Sensitivity of Rapid Antigen Test Is Associated with a Lower Viral Load of Omicron than Delta SARS-CoV-2 Variant.

ABSTRACTLarge-scale screening for SARS-CoV-2 infection is an important tool for epidemic prevention and control. The appearance of new variants associated with specific mutations can call into question the effectiveness of rapid diagnostic tests (RDTs) deployed massively at national and international levels. We compared the clinical and virological characteristics of individuals infected by Delta or Omicron variants to assess which factors were associated with a reduced performance of RDT. A commercially available RDT as well as the evaluation of the viral load (VL) and the detection of replicate intermediates (RIs) were carried out retrospectively on positive SARS-CoV-2 nasopharyngeal specimens from health care workers of the Pitié-Salpêtrière Hospital infected by the Delta or Omicron variant between July 2021 and January 2022. Of the 205 samples analyzed (104 from individuals infected with Delta and 101 with Omicron), 176 were analyzed by RDT and 200 by RT-PCR for VL and RIs. The sensitivity of the TDR for Omicron was significantly lower than that observed for Delta (53.8% versus 74.7%, respectively, P < 0.01). Moreover, the Delta VL was significantly higher than that measured for Omicron (median Ct 21.2 versus 24.1, respectively, P < 0.01) and associated with the positivity of the RDT in multivariate analysis. We demonstrate a lower RDT sensitivity associated with a lower VL at the time of diagnosis on Omicron-infected individuals in comparison to those infected with the Delta variant. This RDT lower sensitivity should be taken into account in the large-scale screening strategy and in particular in case of strong suspicion of infection where testing should be repeated.IMPORTANCE Previous reports have shown a variability in the diagnostic performance of RDTs. In the era of SARS-CoV-2 variants and the use of RDT, mutation associated with these variants could affect the test performance. We evaluate the sensitivity of the RDT Panbio COVID-19 Ag (Abbott) with two variants of concern (VOC), the Delta and Omicron variants. In order to investigate whether clinical characteristics or virological characteristics can affect this sensitivity, we collected clinical information and performed a specific RT-PCR that detected the RIs as a marker of the viral replication and viral cycle stage. Our results showed that Omicron was less detected than the Delta variant. A lower viral load of Omicron variant in comparison to Delta variant explained this decreased sensitivity, even if they are at the same stage of the disease and the viral cycle and should be taken into account with the use of RDT as diagnostic tool.

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.

Rapid antigen testing by community health workers for detection of SARS-CoV-2 in Dhaka, Bangladesh: a cross-sectional study

ObjectiveTo evaluate the diagnostic performance and feasibility of rapid antigen testing for SARS-CoV-2 detection in low-income communities.DesignWe conducted a cross-sectional community-based diagnostic accuracy study. Community health workers, who were trained...

An Agreement of Antigen Tests on Oral Pharyngeal Swabs or Less Invasive Testing With Reverse Transcription Polymerase Chain Reaction for Detecting SARS-CoV-2 in Adults: Protocol for a Prospective Nationwide Observational Study.

BackgroundThe SARS-CoV-2 pandemic has resulted in an unprecedented level of worldwide testing for epidemiologic and diagnostic purposes, and due to the extreme need for tests, the gold-standard Reverse Transcription Polymerase Chain Reaction (RT-PCR) testing capacity has been unable to meet the overall worldwide testing demand. Consequently, although the current literature has shown the sensitivity of rapid antigen tests (RATs) to be inferior to RT-PCR, RATs have been implemented on a large scale without solid data on performance.ObjectiveThis study will compare analytical and clinical sensitivities and specificities of 50 lateral flow– or laboratory-based RATs and 3 strand invasion–based amplification (SIBA)-RT-PCR tests from 30 manufacturers to RT-PCR testing of samples obtained from the deep oropharynx. In addition, the study will compare sensitivities and specificities of the included RATs as well as RT-PCR on clinical samples obtained from the deep oropharynx, the anterior nasal cavity, saliva, the deep nasopharynx, and expired air to RT-PCR on deep oropharyngeal samples.MethodsIn the prospective part of the study, 200 individuals found SARS-CoV-2 positive and 200 individuals found SARS-CoV-2 negative by routine RT-PCR testing will be retested with each RAT, applying RT-PCR as the reference method. In the retrospective part of the study, 304 deep oropharyngeal cavity swabs divided into 4 groups based on RT-PCR quantification cycle (Cq) levels will be tested with each RAT.ResultsThe results will be reported in several papers with different aims. The first paper will report retrospective (analytical sensitivity, overall and stratified into different Cq range groups) and prospective (clinical sensitivity) data for RATs, with RT-PCR as the reference method. The second paper will report results for RAT based on anatomical sampling location. The third paper will compare different anatomical sampling locations by RT-PCR testing. The fourth paper will focus on RATs that rely on central laboratory testing. Tests from 4 different manufacturers will be compared for analytical performance data on retrospective deep oropharyngeal swab samples. The fifth paper will report the results of 4 RATs applied both as professional use and as self-tests. The last paper will report the results from 2 breath tests in the study. A comparison of sensitivity and specificity between RATs will be conducted using the McNemar test for paired samples and the chi-squared test for unpaired samples. Comparison of the positive predictive value (PPV) and negative predictive value (NPV) between RATs will be performed by the bootstrap test, and 95% CIs for sensitivity, specificity, PPV, and NPV will be calculated as bootstrap CIs.ConclusionsThe study will compare the sensitivities of a large number of RATs for SARS-CoV-2 to with those of RT-PCR and will address whether lateral flow–based RATs differ significantly from laboratory-based RATs. The anatomical test locations for both RATs and RT-PCR will also be compared.Trial RegistrationClinicalTrials.gov NCT04913116; https://clinicaltrials.gov/ct2/show/NCT04913116International Registered Report Identifier (IRRID)DERR1-10.2196/35706

Halo-A Universal Fluorescence Reader Based Threat Agent Detection Platform-A Proof of Concept Study Using SARS-CoV-2 Assays.

Polymerase chain reaction (PCR) remains the gold standard in disease diagnostics due to its extreme sensitivity and specificity. However, PCR tests are expensive and complex, require skilled personnel and specialized equipment to conduct the tests, and have long turnaround times. On the other hand, lateral flow immunoassay-based antigen tests are rapid, relatively inexpensive, and can be performed by untrained personnel at the point of care or even in the home. However, rapid antigen tests are less sensitive than PCR since they lack the inherent target amplification of PCR. It has been argued that rapid antigen tests are better indicators of infection in public health decision-making processes to test, trace, and isolate infected people to curtail further transmission. Hence, there is a critical need to increase the sensitivity of rapid antigen tests and create innovative solutions to achieve that goal. Herein, we report the development of a low-cost diagnostic platform, enabling rapid detection of SARS-CoV-2 under field or at-home conditions. This platform (Halo™) is a small, highly accurate, consumer-friendly diagnostic reader paired with fluorescently labeled lateral flow assays and custom software for collection and reporting of results. The focus of this study is to compare the analytical performance of HaloTM against comparable tests that use either colloidal gold nanoparticles or fluorescence-based reporters in simulated nasal matrix and not in clinical samples. Live virus data has demonstrated limit of detection performance of 1.9 TCID50/test in simulated nasal matrix for the delta variant, suggesting that single-assay detection of asymptomatic SARS-CoV-2 infections may be feasible. Performance of the system against all tested SARS CoV-2 virus variants showed comparable sensitivities indicating mutations in SARS-CoV-2 variants do not negatively impact the assay.

Clinical sensitivity of rapid antigen test during a COVID-19 outbreak in Taipei, May to June 2021

Background/purposeThis population-based study aimed to compare the accuracy of Rapid antigen detection (RAD) and reverse transcription-polymerase chain reaction (RT-PCR) assays for diagnosing individuals infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during the COVID-19 outbreak in Taipei, from May to June 2021.MethodsIn response to the outbreak of COVID-19 in mid-May 2021, Taipei City Hospital set up 12 citywide proactive community testing (PCT) stations for early identification of infected individuals from May 17 to June 20, 2021. Individuals with RAD positivity were isolated and later confirmed by RT-PCR. The c-statistic value was estimated to indicate the level of diagnostic accuracy of RAD tests.ResultsOf the 33,798 individuals who were evaluated for SARS-CoV-2 infection, 4.4% tested positive for RAD. There was a moderate concordance (kappa = 0.67) between the RAD tests and RT-PCR assay for identifying infectious individuals. The c-statistic value of the RAD test for the diagnosis of SARS-CoV-2 infection was 0.8. There was a positive linear trend between the accuracy of the RAD tests and the prevalence of SARS-CoV-2 infection in the study population (β = 0.04; p = .03). As the cycle threshold value decreased, the sensitivity rate of the RAD tests increased (p < .001). After implementation of the PCT program, the prevalence of COVID-19 decreased from 8.4% to 3.3% (p < .001).ConclusionProactive community testing for SARS-CoV-2 infection using RAD tests could rapidly identify and quarantine the most infectious patients in the early phase of COVID-19 outbreak.

Diagnostic Strategies for Endemic Coronavirus Disease 2019 (COVID-19).

Coronavirus disease 2019 (COVID-19) rapid antigen tests generate intrinsically fast, inherently spatial, and immediately actionable results. They quickly confirm COVID-19, but weakly rule out infection. Test performance depends on prevalence and testing protocol. Both affect predictive values. To use original mathematics and visual logistics for interpreting COVID-19 rapid antigen test performance patterns, gauge the influence of prevalence, and evaluate repeated testing. Mathematica and open access software helped graph relationships, perform recursive computations, and compare performance patterns. PubMed retrieved articles addressing endemic COVID-19 were reviewed. Tiered sensitivity/specificity comprise the following: T1 (90%/95%), T2 (95%/97.5%), and T3 (100%/≥99%). Performance of self-tests and home antigen tests with US Food and Drug Administration Emergency Use Authorization peaks in low prevalence. Fall-off in performance appears with increasing prevalence because suboptimal sensitivity creates false negatives. The rate of false omissions limits clinical use because of prevalence boundaries based on tolerance for risk. Mathematical analysis supports testing twice to improve predictive values and extend prevalence boundaries nearly to levels of herd immunity. COVID-19 is quickly becoming endemic. Suboptimal sensitivity of rapid antigen tests limits performance in high prevalence. Risk of contagion in packed spaces (eg, airplanes) might be avoided with dual testing 36 hours apart, allowing time for viral load to increase. Awareness of community prevalence and proof of improved performance with repeated testing will help manage COVID-19 risk, while meeting rapid decision-making needs for highly contagious and new variants (eg, Delta). New COVID-19 variants call for high-quality, low cost, readily accessible, fast, user friendly, and ubiquitous point-of-care testing.

Influenza Screening via Deep Learning Using a Combination of Epidemiological and Patient-Generated Health Data: Development and Validation Study.

BackgroundScreening for influenza in primary care is challenging due to the low sensitivity of rapid antigen tests and the lack of proper screening tests.ObjectiveThe aim of this study was to develop a machine learning–based screening tool using patient-generated health data (PGHD) obtained from a mobile health (mHealth) app.MethodsWe trained a deep learning model based on a gated recurrent unit to screen influenza using PGHD, including each patient’s fever pattern and drug administration records. We used meteorological data and app-based surveillance of the weekly number of patients with influenza. We defined a single episode as the set of consecutive days, including the day the user was diagnosed with influenza or another disease. Any record a user entered 24 hours after his or her last record was considered to be the start of a new episode. Each episode contained data on the user’s age, gender, weight, and at least one body temperature record. The total number of episodes was 6657. Of these, there were 3326 episodes within which influenza was diagnosed. We divided these episodes into 80% training sets (2664/3330) and 20% test sets (666/3330). A 5-fold cross-validation was used on the training set.ResultsWe achieved reliable performance with an accuracy of 82%, a sensitivity of 84%, and a specificity of 80% in the test set. After the effect of each input variable was evaluated, app-based surveillance was observed to be the most influential variable. The correlation between the duration of input data and performance was not statistically significant (P=.09).ConclusionsThese findings suggest that PGHD from an mHealth app could be a complementary tool for influenza screening. In addition, PGHD, along with traditional clinical data, could be used to improve health conditions.

Panbio antigen rapid test is reliable to diagnose SARS-CoV-2 infection in the first 7 days after the onset of symptoms

• The new antigen test is an indispensable tool in the control of the pandemic due to its adequate sensitivity and specificity. • The implementation of the point of care technique in primary care is feasible and has good results. • Results of the antigen techniques are determined by an onset of symptoms inferior to five days and a CT below 27 in PCR. RT-qPCR is the current recommended laboratory method to diagnose SARS-CoV-2 acute infection, several factors such as requirement of special equipment, time consuming, high cost and skilled staff limit the use of these techniques. A more rapid and high-throughput method is essential. We analyzed clinical data and nasopharyngeal samples, collected during September 2020, from patients attended at the emergency department of a secondary hospital and in two primary healthcare centers in Madrid. The performance of the Panbio™ COVID-19 AG Rapid Test Device for the detection of SARS-CoV-2 antigen was compared to RT-qPCR. 255 nasopharyngeal swabs, including 150 from the emergency department and 105 from primary helthcare centers, were tested. 184 patients were symptomatic (72.1 %). Amongst the 60 positive RT-qPCR samples, 40 were detected by the rapid antigen test, given an overall sensitivity of 73.3 %. All the samples detected positive with the rapid antigen test were also positive with RT-qPCR. The median cycle threshold was 23.28 (IQR 18.5–30.16). Patients with less than seven days onset of symptoms showed a higher viral load, and sensitivity for rapid antigen test (86.5 %), compared to those with more days (sensitivity of 53.8 %)(p < 0.004). The rapid antigen test evaluated in this study showed a high sensitivity and specificity in samples obtained during the first week of symptoms and with high viral loads. This assay seems to be an effective strategy for controlling the COVID-19 pandemic for the rapid identification and isolation of SARS-CoV-2 infected patients.

Commentary

Commentary

Rapid-Test Sensitivity for Novel Swine-Origin Influenza A (H1N1) Virus in Humans

To the Editor: Faix et al. (Aug. 13 issue)1 highlight the moderate sensitivity of rapid antigen tests as compared with reverse-transcriptase–polymerase-chain-reaction (RT-PCR) assays in detecting the 2009 pandemic influenza A (H1N1) virus in infected patients. We found that the antigen tests had poor sensitivity to the virus when used in a subgroup of 21 patients in the Australian intensive care cohort with severe 2009 influenza A (H1N1) virus infection and acute lung injury that required mechanical ventilation.2 In these patients, rapid antigen tests (QuickVue A+B, Quidel) were performed on swabs from the nose and throat, and influenza type-specific immunofluorescent antigen . . .

Lack of sensitivity of rapid antigen tests for the diagnosis of respiratory syncytial virus infection in adults.

The diagnosis of respiratory syncytial virus (RSV) infection in older individuals and adults with cardiopulmonary diseases using available rapid antigen detection tests may be difficult due to the low virus shedding in this population. These tests have been extensively evaluated in hospitalized infants, but there is only limited data on their usefulness in adult populations. We evaluated the performance of three different rapid antigen detection tests: Becton Dickinson Directigen RSV (BD), Bartels RSV Direct Fluorescent Antibody Test (DFA) and the VIDAS RSV assay (VIDAS) in nasopharyngeal specimens from 60 older persons with RSV infection documented by cell culture, serology or reverse transcription polymerase chain reaction (RT-PCR). The three rapid antigen assays tested on all 60 samples performed poorly. DFA detected 14 (23%), VIDAS detected 12 (20%) and BD detected only 6 (10%) of the RSV infected persons. Rapid antigen detection tests for the diagnosis of RSV respiratory illness in adults are of limited value.