scholarly journals ImplemeNting SARS-CoV-2 Rapid antigen testing in the Emergency wArd of a Swiss univErsity hospital: the INCREASE study

2021 ◽  
Author(s):  
Giorgia Caruana ◽  
Antony Croxatto ◽  
Eleftheria Kampouri ◽  
Antonios Kritikos ◽  
Onya Opota ◽  
...  
Keyword(s):  
University Hospital ◽  
Lower Sensitivity ◽  
Clinical Settings ◽  
Rt Pcr ◽  
Emergency Ward ◽  
Viral Loads ◽  
Molecular Tests ◽  
One Step ◽  
Antigen Tests ◽  
Second Wave

BackgroundWhile facing a second wave in SARS-CoV-2 pandemic, in November 2020 the Swiss Federal Office of Public Health (FOPH) authorized the use of rapid antigen tests (RATs) in addition to the gold-standard reverse transcription-polymerase chain reaction (RT-PCR).MethodsWe implemented the use of RAT in the emergency ward of our university hospital for rapid patients’ triaging and compared performances of four different antigen tests. All results were compared to SARS-CoV-2 specific RT-PCR (reference standard).ResultsTriaging patients using RAT in association with RT-PCR allowed us to isolate promptly positive patients and to save resources, in a context of rapid RT-PCR reagents shortage. Among 532 patients with valid results, overall sensitivities were 48.3% for One Step Exdia and 41.2% for Standard Q®, Panbio−and BD Veritor. All four antigen tests exhibited specificity above 99%. Sensitivity increased up to 74.6%, 66.2%, 66.2% and 64.8% for One Step Exdia, Standard Q, Panbio, and BD Veritor respectively, when considering viral loads above 105copies/ml, up to 100%, 97.8%, 96.6% and 95.6% for viral loads above 106 copies/ml and 100% (for all tests) when considering viral loads above 107 copies/ml. Sensitivity was significantly higher for patients presenting with symptoms onset within 4 days (74.3%, 69.2%, 69.2% and 64%, respectively) versus patients with evolution of symptoms for more than 4 days (36.8%, 21.1%, 21.1% and 23.7%, respectively). Sensitivities of all RAT assays were of only 33% among hospitalized patients without COVID-19 symptoms.ConclusionRAT might represent a useful epidemiological resource in selected clinical settings as a complementary tool to the molecular tests for rapid patients triaging, but the lower sensitivity compared to RT-PCR, especially in late presenters and subjects without COVID-19 symptoms, must be taken into account in order to correctly use RAT for triaging.

scholarly journals Implementing SARS-CoV-2 Rapid Antigen Testing in the Emergency Ward of a Swiss University Hospital: The INCREASE Study

2021 ◽  
Vol 9 (4) ◽  
pp. 798
Author(s):  
Giorgia Caruana ◽  
Antony Croxatto ◽  
Eleftheria Kampouri ◽  
Antonios Kritikos ◽  
Onya Opota ◽  
...  
Keyword(s):  
Immunoglobulin A ◽  
University Hospital ◽  
Lower Sensitivity ◽  
Clinical Settings ◽  
Rt Pcr ◽  
Emergency Ward ◽  
Viral Loads ◽  
Asymptomatic Patients ◽  
Asymptomatic Subjects ◽  
Antigen Testing

Following the Swiss Federal Office of Public Health (FOPH) authorization of the rapid antigen test (RAT), we implemented the use of the RAT in the emergency ward of our university hospital for patients’ cohorting. RAT triaging in association with RT-PCR allowed us to promptly isolate positive patients and save resources. Among 532 patients, overall sensitivities were 48.3% for Exdia and 41.2% for Standard Q®, PanbioTM and BD Veritor™. All RATs exhibited specificity above 99%. Sensitivity increased to 74.6%, 66.2%, 66.2% and 64.8% for Exdia, Standard Q®, PanbioTM and BD Veritor™, respectively, for viral loads above 105 copies/mL, to 100%, 97.8%, 96.6% and 95.6% for viral loads above 106 copies/mL and 100% for viral loads above 107 copies/mL. Sensitivity was significantly higher for patients with symptoms onset within four days (74.3%, 69.2%, 69.2% and 64%, respectively) versus patients with the evolution of symptoms longer than four days (36.8%, 21.1%, 21.1% and 23.7%, respectively). Among COVID-19 asymptomatic patients, sensitivity was 33%. All Immunoglobulin-A-positive patients resulted negative for RAT. The RAT might represent a useful resource in selected clinical settings as a complementary tool in RT-PCR for rapid patient triaging, but the lower sensitivity, especially in late presenters and COVID-19 asymptomatic subjects, must be taken into account.

scholarly journals Sensitivity of rapid antigen testing and RT-PCR performed on nasopharyngeal swabs versus saliva samples in COVID-19 hospitalized patients: results of a prospective comparative trial (RESTART)

2021 ◽  
Author(s):  
Antonios Kritikos ◽  
Giorgia Caruana ◽  
René Brouillet ◽  
John-Paul Miroz ◽  
Abed-Maillard Samia ◽  
...  
Keyword(s):  
Comparative Trial ◽  
Hospitalized Patients ◽  
Rt Pcr ◽  
Duration Of Symptoms ◽  
Non Invasive ◽  
Viral Transport Medium ◽  
One Step ◽  
Antigen Tests ◽  
Low Sensitivity ◽  
Antigen Testing

AbstractObjectivesSaliva sampling could serve as an alternative non-invasive sample for SARS-CoV-2 diagnosis while rapid antigen testing (RAT) might help to mitigate the shortage of reagents sporadically encountered with RT-PCR. Thus, in the RESTART study we compared antigen and RT-PCR testing methods on nasopharyngeal (NP) swabs and salivary samples.MethodsWe conducted a prospective observational study among COVID-19 hospitalized patients between 10th December 2020 and 1st February 2021. Paired saliva and NP samples were investigated by RT-PCR (Cobas 6800, Roche-Switzerland) and by two rapid antigen tests: One Step Immunoassay Exdia® COVID-19 Ag (Precision Biosensor, Korea) and Standard Q® COVID-19 Rapid Antigen Test (Roche-Switzerland).ResultsA total of 58 paired NP-saliva specimens were collected. Thirty-two of 58 (55%) patients were hospitalized in the intensive care unit and the median duration of symptoms was 11 days (IQR 5-19). NP and salivary RT-PCR exhibited sensitivity of 98% and 69% respectively whereas the specificity of these RT-PCRs assays were of 100%. NP RAT exhibited much lower diagnostic performances with sensitivities of 35% and 41% for the Standard Q® and Exdia® assays respectively, when a wet-swab approach was used (i.e. when the swab was diluted in the viral transport medium (VTM) before testing). The sensitivity of the dry-swab approach was slightly better (47%). These antigen tests exhibited very low sensitivity (4 and 8%) when applied to salivary swabs.ConclusionsNasopharyngeal RT-PCR is the most accurate test for COVID-19 diagnosis in hospitalized patients. RT-PCR on salivary samples may be used when nasopharyngeal swabs are contraindicated. RAT are not appropriate for hospitalized patients.

scholarly journals Evaluation of rapid SARS-CoV-2 antigen tests, AFIAS COVID-19 Ag and ichroma COVID-19 Ag, with serial nasopharyngeal specimens from COVID-19 patients

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0249972
Author(s):  
Oh Joo Kweon ◽  
Yong Kwan Lim ◽  
Hye Ryoun Kim ◽  
Yoojeong Choi ◽  
Min-Chul Kim ◽  
...  
Keyword(s):  
Early Detection ◽  
Point Of Care ◽  
Molecular Testing ◽  
Test Results ◽  
Molecular Test ◽  
Viral Loads ◽  
Molecular Tests ◽  
Antigen Tests ◽  
Diagnostic Sensitivity And Specificity ◽  
Negative Controls

We evaluated the diagnostic accuracy of two newly developed, point-of-care, rapid antigen tests (RATs) for detecting SARS-CoV-2, the AFIAS COVID-19 Ag and the ichromaTM COVID-19 Ag, and investigated antigen kinetics. A total of 200 serially collected nasopharyngeal (NP) specimens from 38 COVID-19 patients and 122 specimens from negative controls were analyzed. Diagnostic sensitivity and specificity were assessed in comparison to molecular test results and subdivided according to targeted genes (E, RdRP, and N) and days post-symptom onset (PSO). For the kinetics evaluation, cut-off-indices from serial NP specimens were used according to the number of days PSO. Both RATs showed sensitivity of 91.3‒100% for specimens with cycle threshold (Ct) < 25. The specificity of AFIAS was 98.7‒98.9% and that of ichromaTM was 100.0%. The kappa values of AFIAS and ichromaTM for the molecular testing of specimens with Ct < 25 (RdRP) were 0.97 and 1.00, respectively. The sensitivity of AFIAS and ichromaTM for all genes was lower for specimens collected at 8‒14 PSO than for those collected before 7-days PSO. The kinetics profiles showed that antigen levels gradually decreased from ≤ 7-days PSO to > 22-days PSO. Both RATs showed excellent specificity and acceptable sensitivity for NP specimens with higher viral loads and for specimens collected within 7-days PSO. Hence, they have the potential to become useful tools for the early detection of SARS-CoV-2. However, because of concerns about false negativity, RATs should be used in conjunction with molecular tests.

scholarly journals The Efficacy of General Practitioner Assessment of Cognition in Chinese Elders Aged 80 and Older

2019 ◽  
Vol 34 (7-8) ◽  
pp. 523-529
Author(s):  
Fang Xu ◽  
Juan Juan Ma ◽  
Fei Sun ◽  
Jaewon Lee ◽  
David W. Coon ◽  
...  
Keyword(s):  
General Practitioner ◽  
Mini Mental State Examination ◽  
Mainland China ◽  
University Hospital ◽  
Comparable Efficacy ◽  
Lower Sensitivity ◽  
Clinical Settings ◽  
Older Chinese ◽  
State Examination ◽  
Survey Questionnaires

Objectives: This study examined the efficacy of the General Practitioner Assessment of Cognition–Chinese version (GPCOG-C) in screening dementia and mild cognitive impairment (MCI) among older Chinese. Methods: Survey questionnaires were administered to 293 participants aged 80 or above from a university hospital in mainland China. Alzheimer disease and MCI were diagnosed in light of the National Institute on Aging and the Alzheimer’s Association (NIA/AA) criteria. The sensitivity and specificity of GPCOG-C and Mini-Mental State Examination (MMSE) in screening dementia and MCI were compared to the NIA/AA criteria. Results: The GPCOG-C had the sensitivity of 62.3% and specificity of 84.6% in screening MCI, which had comparable efficacy as the NIA/AA criteria. In screening dementia, GPCOG-C had a lower sensitivity (63.7%) than the MMSE and a higher specificity (82.6%) higher than the MMSE. Conclusions: The GPCOG-C is a useful and efficient tool to identify dementia and MCI in older Chinese in outpatient clinical settings.

scholarly journals A laboratory-based study of COVID-19 in Casablanca, Morocco

2020 ◽  
Author(s):  
Idrissa Diawara ◽  
Houda Benrahma ◽  
Nida Meskaouni ◽  
Jalila Rahoui ◽  
Fatima-Zahra Moujid ◽  
...  
Keyword(s):  
Clinical Symptoms ◽  
Laboratory Diagnosis ◽  
University Hospital ◽  
Reference Laboratory ◽  
Rt Pcr ◽  
Exposure Risk ◽  
Cross Sectional ◽  
Risk Zone ◽  
Laboratory Confirmation ◽  
One Step

Background: Given the spread of coronavirus disease 2019 (COVID-19) and its impact on human health, laboratory confirmation of diagnosis is essential. Objective: This study examined the contribution of laboratory diagnosis to the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the diagnosis of COVID- 19, taking into account patient risk of exposure to SARS-CoV-2, clinical symptoms and comorbidities. Methods: A cross-sectional, laboratory-based study was carried out from 1 April 2020 to 30 April 2020 at the National Reference Laboratory in Morocco using nasopharyngeal samples from patients admitted to the Cheikh Khalifa International University Hospital or other hospitals in Casablanca. A one-step reverse transcription real-time polymerase chain reaction (RT-PCR) was used to detect the presence of the SARS-CoV-2 genome. A national epidemiological investigation form was used to analyze patient exposure risk, clinical symptoms and comorbidities. Results: A total of 793 samples from 375 patients were analyzed and 1150 RT-PCR tests were conducted; 116 patients (30.93%) were COVID-19 positive. Travel to a risk zone, contact with a confirmed COVID-19 case and contact with a person who had been in a risk zone were significantly associated with being positive for COVID-19. Fever and cough were the main symptoms; 7.76 % of positive patients were asymptomatic. Conclusion: This is the first laboratory-based study in Morocco for the diagnosis of COVID- 19. Laboratory diagnosis of COVID-19 by RT-PCR associated with knowledge of exposure risk factors and clinical symptoms and comorbidities remains essential for clinicians for early, appropriate medical management COVID-19 patients.

scholarly journals Potential Use of Antigen-Based Rapid Test for SARS-CoV-2 in Respiratory Specimens in Low-Resource Settings in Egypt for Symptomatic Patients and High-Risk Contacts

2020 ◽  
Author(s):  
Abeer Mohamed Abdelrazik ◽  
Shahira Morsy Elshafie ◽  
Hossam M Abdelaziz
Keyword(s):  
Test Performance ◽  
Healthcare Professionals ◽  
Rapid Test ◽  
University Hospital ◽  
Antigen Test ◽  
Rt Pcr ◽  
Viral Loads ◽  
Viral Transport Medium ◽  
Public Health Challenges ◽  
Polymerase Chain

Abstract Objective Because of the rapidly emerging SARS-CoV-2 pandemic and its wide public health challenges, rapid diagnosis is essential to decrease the spread. Antigen-based rapid detection tests are available; however, insufficient data about their performance are available. Methods The lateral-flow immunochromatographic BIOCREDIT COVID-19 antigen test was evaluated using nasopharyngeal swabs in a viral transport medium from patients with confirmed infection, contacts, and exposed healthcare professionals at Fayoum University Hospital in Egypt. Test performance was determined in comparison to the SARS-CoV-2 real-time reverse-transcription polymerase chain reaction (RT-PCR) test. Results Three hundred ten specimens from 3 categories—patients with confirmed diagnoses of COVID-19, contacts, and exposed healthcare professionals—were included; 188 specimens were RT-PCR-positive, from which 81 were detected by rapid antigen test. Overall sensitivity was 43.1%. Sensitivity was significantly higher in specimens with high viral loads. Conclusion Poor sensitivity of the BIOCREDIT COVID-19 test does not permit its use for diagnosis, and it can only be used in conjunction with RT-PCR for screening.

scholarly journals The Performance of Two Rapid Antigen Tests During Population-Level Screening for SARS-CoV-2 Infection

2021 ◽  
Vol 8 ◽  
Author(s):  
Mohammad Alghounaim ◽  
Hamad Bastaki ◽  
Farah Bin Essa ◽  
Hoda Motlagh ◽  
Salman Al-Sabah
Keyword(s):  
Positive Predictive Value ◽  
Prospective Study ◽  
Predictive Value ◽  
Point Of Care ◽  
Population Level ◽  
Lower Sensitivity ◽  
Rt Pcr ◽  
Antigen Tests ◽  
A Prospective Study ◽  
Antigen Testing

Background: SARS-CoV-2 antigen assays offer a rapid mean to diagnose and isolate infected individuals. However, their utility in population-level screening is unknown.Objectives: The performance of two antigen tests in detecting SARS-CoV-2 was assessed among individuals randomly selected in the community.Study Design: A prospective study that performed head-to-head comparison of two SARS-CoV-2 antigen assays. Individuals were recruited during community SARS-CoV-2 screening over 10 working days. Demographic and clinical data were collected. Standard Q COVID-19 Ag test, a point-of-care chromatographic assay, was conducted immediately, and then the sample was transported to the virology laboratory to perform PCR and the LIAISON SARS-CoV-2 Ag chemiluminesence immunoassay.Results: respiratory samples from 991 individuals were collected, and 62 were positive by PCR. Inconclusive PCR results were observed in 19 samples and were excluded. The median age of participants was 40.2 years (IQR 32.3–47.8), and 932 (94%) were males. Most (77.4%) of infections were asymptomatic. The sensitivity and the specificity of the LIAISON assay were 43.3% (95%CI 30.6–56.8) and 99.9% (95%CI 99.3–100). The Standard Q assay had lower sensitivity (30.6%, 95%CI 19.6–43.7) but similar specificity (98.8%, 95%CI, 97.8–99.4). Similarly, the LIAISON assay had higher positive predictive value (96.3%, 95%CI 81–99.9% vs. 63.3%, 95%CI, 43.9–80.1%). Both assays performed better in symptomatic patients and among samples with a low-cycle threshold (Ct &lt; 25).Conclusion: In our setting of random community surveillance, rapid antigen testing of nasopharyngeal swabs by either LIAISON SARS-CoV-2 Ag (DiaSorin) or Standard Q COVID-19 Ag (SD Biosensor) was less sensitive to detecting SARS-CoV-2 than the TaqPath COVID-19 RT-PCR.

scholarly journals Evaluation of Rapid Antigen Tests Using Nasal Samples to Diagnose SARS-CoV-2 in Symptomatic Patients

2022 ◽  
Vol 9 ◽  
Author(s):  
Manaf Alqahtani ◽  
Abdulkarim Abdulrahman ◽  
Fathi Mustafa ◽  
Abdulla I. Alawadhi ◽  
Batool Alalawi ◽  
...  
Keyword(s):  
Early Detection ◽  
Nasal Swab ◽  
Cost Effective ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Rapid Antigen Detection Test ◽  
Viral Loads ◽  
Antigen Tests ◽  
Stratified Analysis ◽  
Potential Use

IntroductionThe best way to mitigate an outbreak besides mass vaccination is via early detection and isolation of infected cases. As such, a rapid, cost-effective test for the early detection of COVID-19 is required.MethodsThe study included 4,183 mildly symptomatic patients. A nasal and nasopharyngeal sample obtained from each patient was analyzed to determine the diagnostic ability of the rapid antigen detection test (RADT, nasal swab) in comparison with the current gold-standard (RT-PCR, nasopharyngeal swab).ResultsThe calculated sensitivity and specificity of the RADT was 82.1 and 99.1%, respectively. Kappa's coefficient of agreement between the RADT and RT-PCR was 0.859 (p &lt; 0.001). Stratified analysis showed that the sensitivity of the RADT improved significantly when lowering the cut-off RT-PCR Ct value to 24.ConclusionOur study's results support the potential use of nasal swab RADT as a screening tool in mildly symptomatic patients, especially in patients with higher viral loads.

scholarly journals Characteristics of children and antigen test performance at a SARS-CoV-2 community testing site

2021 ◽  
Author(s):  
Laura Ford ◽  
Melissa J. Whaley ◽  
Melisa M. Shah ◽  
Phillip P. Salvatore ◽  
Hannah E. Segaloff ◽  
...  
Keyword(s):  
Test Performance ◽  
Point Of Care ◽  
Lower Sensitivity ◽  
Antigen Test ◽  
Rt Pcr ◽  
Culture Methods ◽  
Viral Culture ◽  
Asymptomatic Children ◽  
Testing Site ◽  
Antigen Tests

Background: Performance characteristics of SARS-CoV-2 antigen tests among children are limited despite the need for point-of-care testing in school and childcare settings. We describe children seeking SARS-CoV-2 testing at a community site and compare antigen test performance to real-time reverse transcription-polymerase chain reaction (RT-PCR) and viral culture. Methods: Two anterior nasal specimens were self-collected for BinaxNOW antigen and RT-PCR testing, along with demographics, symptoms, and exposure information from individuals ≥5 years at a community testing site. Viral culture was attempted on residual antigen or RT-PCR positive specimens. Demographic and clinical characteristics, and the performance of SARS-CoV-2 antigen tests, were compared among children (<18 years) and adults. Results: About one in ten included specimens were from children (225/2110); 16.4% (37/225) were RT-PCR positive. Cycle threshold values were similar among RT-PCR positive specimens from children and adults (22.5 vs 21.3, p=0.46) and among specimens from symptomatic and asymptomatic children (22.5 vs 23.2, p=0.39). Sensitivity of antigen test compared to RT-PCR was 73.0% (27/37) among specimens from children and 80.8% (240/297) among specimens from adults; among specimens from children, specificity was 100% (188/188), positive and negative predictive value were 100% (27/27) and 94.9% (188/198) respectively. Virus was isolated from 51.4% (19/37) of RT-PCR positive pediatric specimens; all 19 had positive antigen test results. Conclusions : With lower sensitivity relative to RT-PCR, antigen tests may not diagnose all positive COVID-19 cases; however, antigen testing identified children with live SARS-CoV-2 virus.

scholarly journals Evaluation of the SARS-CoV-2 positivity ratio and upper respiratory tract viral load among asymptomatic individuals screened before hospitalization or surgery in Flanders, Belgium

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0259908
Author(s):  
Laura Heireman ◽  
Steven Abrams ◽  
Peggy Bruynseels ◽  
Reinoud Cartuyvels ◽  
Lize Cuypers ◽  
...  
Keyword(s):  
Viral Load ◽  
Respiratory Tract ◽  
Age Group ◽  
Test Results ◽  
Rt Pcr ◽  
Median Viral Load ◽  
Viral Loads ◽  
Asymptomatic Patients ◽  
Positivity Ratio ◽  
Second Wave

Introduction The incidence of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infections in the Belgian community is mainly estimated based on test results of patients with coronavirus disease (COVID-19)-like symptoms. The aim of this study was to investigate the evolution of the SARS-CoV-2 reverse transcriptase polymerase chain reaction (RT-PCR) positivity ratio and distribution of viral loads within a cohort of asymptomatic patients screened prior hospitalization or surgery, stratified by age category. Materials/Methods We retrospectively studied data on SARS-CoV-2 real-time RT-PCR detection in respiratory tract samples of asymptomatic patients screened pre-hospitalization or pre-surgery in nine Belgian hospitals located in Flanders over a 12-month period (1 April 2020–31 March 2021). Results In total, 255925 SARS-CoV-2 RT-PCR test results and 2421 positive results for which a viral load was reported, were included in this study. An unweighted overall SARS-CoV-2 real-time RT-PCR positivity ratio of 1.27% was observed with strong spatiotemporal differences. SARS-CoV-2 circulated predominantly in 80+ year old individuals across all time periods except between the first and second COVID-19 wave and in 20–30 year old individuals before the second COVID-19 wave. In contrast to the first wave, a significantly higher positivity ratio was observed for the 20–40 age group in addition to the 80+ age group compared to the other age groups during the second wave. The median viral load follows a similar temporal evolution as the positivity rate with an increase ahead of the second wave and highest viral loads observed for 80+ year old individuals. Conclusion There was a high SARS-CoV-2 circulation among asymptomatic patients with a predominance and highest viral loads observed in the elderly. Moreover, ahead of the second COVID-19 wave an increase in median viral load was noted with the highest overall positivity ratio observed in 20–30 year old individuals, indicating they could have been the hidden drivers of this wave.

Sign in / Sign up

Export Citation Format

Share Document