Comparison of seven commercial SARS-CoV-2 rapid point-of-care antigen tests: a single-centre laboratory evaluation study

Background Rapid antigen testing is widely used as a way of scaling up population-level testing. To better inform antigen test deployment in Australia, we evaluated 22 commercially available antigen tests, including an assessment of culture infectivity. Methods Analytical sensitivity was evaluated against SARS-CoV-2 B.1.617.2 (Delta), reported as TCID50/mL, cycle threshold (Ct) value and viral load (RNA copies/mL). Specificity was assessed against non-SARS-CoV-2 viruses. Clinical sensitivity and correlation with cell culture infectivity was assessed using the Abbott PanBio™ COVID-19 Ag test. Results Nineteen kits consistently detected SARS-CoV-2 antigen equivalent to 1.3x10^6 copies/mL (5.8x10^3 TCID50/mL). Specificity for all kits was 100%. Compared to RT-PCR the Abbott PanBio™ COVID-19 Ag test was 52.6% (95% CI, 41.6% to 63.3%) sensitive, with a 50% detection probability for infectious cell culture at 5.9 log10 RNA copies/mL (95% CI, 5.3 to 6.5 log10 copies/mL). Antigen test sensitivity was 97.6% (95% CI, 86.3% to 100.0%) compared to positive infectious in cell culture. Conclusions Antigen test positivity correlated with positive viral culture, suggesting antigen test results may determine SARS-CoV-2 transmission risk. Sensitivity varied considerably between test kits and highlights the need for ongoing systematic post-market evaluation, providing valuable information to help guide antigen test selection and deployment.

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Comparison of four commercial, automated antigen tests to detect SARS-CoV-2 variants of concern

Medical Microbiology and Immunology ◽

10.1007/s00430-021-00719-0 ◽

2021 ◽

Author(s):

Andreas Osterman ◽

Maximilian Iglhaut ◽

Andreas Lehner ◽

Patricia Späth ◽

Marcel Stern ◽

...

Keyword(s):

Nucleic Acid ◽

Point Of Care ◽

Study Cohort ◽

Operating Characteristics ◽

Testing Strategies ◽

Level 3 ◽

Amino Acid Mutations ◽

Antigen Tests ◽

Roche Diagnostics ◽

Analytical Sensitivities

AbstractA versatile portfolio of diagnostic tests is essential for the containment of the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) pandemic. Besides nucleic acid-based test systems and point-of-care (POCT) antigen (Ag) tests, quantitative, laboratory-based nucleocapsid Ag tests for SARS-CoV-2 have recently been launched. Here, we evaluated four commercial Ag tests on automated platforms and one POCT to detect SARS-CoV-2. We evaluated PCR-positive (n = 107) and PCR-negative (n = 303) respiratory swabs from asymptomatic and symptomatic patients at the end of the second pandemic wave in Germany (February–March 2021) as well as clinical isolates EU1 (B.1.117), variant of concern (VOC) Alpha (B.1.1.7) or Beta (B.1.351), which had been expanded in a biosafety level 3 laboratory. The specificities of automated SARS-CoV-2 Ag tests ranged between 97.0 and 99.7% (Lumipulse G SARS-CoV-2 Ag (Fujirebio): 97.03%, Elecsys SARS-CoV-2 Ag (Roche Diagnostics): 97.69%; LIAISON® SARS-CoV-2 Ag (Diasorin) and SARS-CoV-2 Ag ELISA (Euroimmun): 99.67%). In this study cohort of hospitalized patients, the clinical sensitivities of tests were low, ranging from 17.76 to 52.34%, and analytical sensitivities ranged from 420,000 to 25,000,000 Geq/ml. In comparison, the detection limit of the Roche Rapid Ag Test (RAT) was 9,300,000 Geq/ml, detecting 23.58% of respiratory samples. Receiver-operating-characteristics (ROCs) and Youden’s index analyses were performed to further characterize the assays’ overall performance and determine optimal assay cutoffs for sensitivity and specificity. VOCs carrying up to four amino acid mutations in nucleocapsid were detected by all five assays with characteristics comparable to non-VOCs. In summary, automated, quantitative SARS-CoV-2 Ag tests show variable performance and are not necessarily superior to a standard POCT. The efficacy of any alternative testing strategies to complement nucleic acid-based assays must be carefully evaluated by independent laboratories prior to widespread implementation.

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Assessment of SARS-CoV-2 rapid antigen tests

Journal of Laboratory Medicine ◽

10.1515/labmed-2021-0036 ◽

2021 ◽

Vol 45 (3) ◽

pp. 143-148

Author(s):

Mustafa Özcürümez ◽

Antonios Katsounas ◽

Stefan Holdenrieder ◽

Alexander von Meyer ◽

Harald Renz ◽

...

Keyword(s):

Point Of Care ◽

Low Cost ◽

Sources Of Information ◽

Package Inserts ◽

Evaluation Of Performance ◽

Specificity And Sensitivity ◽

Performance Specifications ◽

Antigen Tests ◽

Minimum Criteria ◽

Almost All

Abstract Objectives Point-of-care antigen tests (PoC-AgTs) for the rapid detection of SARS-CoV-2 infection enable screening of additional populations with less effort, independent of laboratories and at a low cost. PoC-AgTs have therefore been included in national testing strategies with additional quality requirements to address limitations in specificity and sensitivity. Information given in the package inserts of the test providers should enable the user to evaluate the performance of a PoC-AgT in advance. The quality of this information has been independently assessed since the Corona Test Ordinance came into force in Germany in October 2020. Methods The completeness of analytical and diagnostic performance specifications was assessed for all package inserts publicly available via the Paul Ehrlich Institute (PEI). It was ascertained whether the minimum criteria, recommendations, and extended criteria of the PEI were comprehensibly fulfilled. The number of tests removed from the list by March 2021 was determined. Results By the closing date of the survey (17.11.2020), the PEI had listed 165 PoC-AgTs that formally fulfilled the minimum criteria and were thus reimbursed. A total of 78 identical systems were identified. Almost all providers were found to have gaps in the information on the validation results of their tests, meaning that an evaluation of performance is only possible to a limited extent. Until March 2021, 25 non-identical PoC-AgTs have been removed from the list. Conclusions Many PoC-AgTs could not be comprehensively evaluated based on the information provided by the provider. Users are therefore dependent on provider-independent sources of information.

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Clinical performance evaluation of SARS-CoV-2 rapid antigen testing in point of care usage in comparison to RT-qPCR

10.1101/2021.03.27.21253966 ◽

2021 ◽

Author(s):

Isabell Wagenhaeuser ◽

Kerstin Knies ◽

Vera Rauschenberger ◽

Michael Eisenmann ◽

Miriam McDonogh ◽

...

Keyword(s):

Performance Evaluation ◽

Viral Load ◽

Clinical Performance ◽

Point Of Care ◽

Hospital Setting ◽

High Viral Load ◽

Evaluation Study ◽

Study Cohort ◽

Protein Variant ◽

Atypical Symptoms

Background Antigen rapid diagnostic tests (RDT) for SARS-CoV-2 are fast, broadly available, and inexpensive. Despite this, reliable clinical performance data is sparse. Methods In a prospective performance evaluation study, RDT from three manufacturers (NADAL, Panbio, MEDsan) were compared to quantitative reverse transcription polymerase chain reaction (RT-qPCR) in 5 068 oropharyngeal swabs for detection of SARS-CoV-2 in a hospital setting. Viral load was derived from standardized RT-qPCR Cycle threshold (Ct) values. The data collection period ranged from November 12, 2020 to February 28, 2021. Findings Overall, sensitivity of RDT compared to RT-qPCR was 42.57% (95% CI 33.38%-52.31%), and specificity 99.68% (95% CI 99.48%-99.80%). Sensitivity declined with decreasing viral load from 100% in samples with a deduced viral load of 10^8 SARS-CoV-2 RNA copies per ml to 8.82% in samples with a viral load lower than 104 SARS-CoV-2 RNA copies per ml. No significant differences in sensitivity or specificity could be observed between the three manufacturers, or between samples with and without spike protein variant B.1.1.7. The NPV in the study cohort was 98.84%; the PPV in persons with typical COVID-19 symptoms was 97.37%, and 28.57% in persons without or with atypical symptoms. Interpretation RDT are a reliable method to diagnose SARS-CoV-2 infection in persons with high viral load. RDT are a valuable addition to RT-qPCR testing, as they reliably detect infectious persons with high viral loads before RT-qPCR results are available. Funding German Federal Ministry for Education and Science (BMBF), Free State of Bavaria

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Accuracy of Two Circulating Antigen Tests for the Diagnosis and Surveillance of Schistosoma mansoni Infection in Low-Endemicity Settings of Côte d’Ivoire

American Journal of Tropical Medicine and Hygiene ◽

10.4269/ajtmh.21-0031 ◽

2021 ◽

Author(s):

Rufin K. Assaré ◽

Mathieu I. Tra-Bi ◽

Jean T. Coulibaly ◽

Paul L. A. M. Corstjens ◽

Mamadou Ouattara ◽

...

Keyword(s):

Schistosoma Mansoni ◽

Cote D'ivoire ◽

Côte D’Ivoire ◽

Point Of Care ◽

Urine Specimen ◽

Cote D’Ivoire ◽

Côte D'ivoire ◽

Circulating Antigen ◽

Antigen Tests ◽

True Infection

In low-endemicity settings, current tools for diagnosis and surveillance of schistosomiasis are often inaccurate in detecting true infection. We assessed the accuracy of an up-converting phosphor lateral flow circulating anodic antigen (UCP-LF CAA) test and a point-of-care circulating cathodic antigen (POC-CCA) urine cassette test for the diagnosis of Schistosoma mansoni. Our study was conducted in eight schools of western Côte d’Ivoire. Fifty children, aged 9 to 12 years, were enrolled per school. From each child, a single urine specimen and two stool specimens were collected over consecutive days for diagnostic workup. Urine samples were subjected to UCP-LF CAA and POC-CCA tests. From each stool sample, triplicate Kato-Katz thick smears were examined. Overall, 378 children had complete data records. The prevalence of S. mansoni, as assessed by six Kato-Katz thick smears, was 4.0%. The UCP-LF CAA and POC-CCA tests revealed S. mansoni prevalence of 25.4% and 30.7%, respectively, when considering trace results as positive, and prevalence of 23.3% and 10.9% when considering trace results as negative. In the latter case, based on a composite gold standard, the sensitivity of UCP-LF CAA (80.7%) was considerably higher than that of POC-CCA (37.6%) and six Kato-Katz thick smears (13.8%). The negative predictive value of UCP-LF CAA, POC-CCA, and six Kato-Katz thick smears was 92.8%, 79.8%, and 74.1%, respectively. Our results confirm that UCP-LF CAA is more accurate than Kato-Katz and POC-CCA for the diagnosis of S. mansoni in low-endemicity settings.

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Performance Evaluation and Multicenter Consistency Study of Smartphone-based Hipee S2 Point-of-care Testing Urine Dipstick Analyser: Evaluation Study (Preprint)

10.2196/preprints.30957 ◽

2021 ◽

Author(s):

Qiang Zhang ◽

Guoqing Wang ◽

Xiaolong Zong ◽

Jinghua Sun

Keyword(s):

Health Management ◽

Clinical Performance ◽

Point Of Care ◽

Method Comparison ◽

Evaluation Study ◽

Analytical Performance ◽

Point Of Care Testing ◽

Urine Dipstick ◽

Quantitative Results ◽

Carry Over

BACKGROUND With advances in mobile technology, smartphone-based point-of-care testing (POCT) urinalysis hold great potential for disease screening and health management for clinicians and individual users. The POCT devices need to have good analytical and clinical performance, but data are lacking. OBJECTIVE The purpose of this study is to evaluate the analytical performance of smartphone-based Hipee S2 POCT urine dipstick analyser. METHODS A total of 1,603 urine samples from three hospitals were collected. Precision, drift, carry-over, interference, and method comparison of Hipee S2 were evaluated. RESULTS The precision for each parameter, assessed by control materials, was acceptable. No sample carry-over or drift was observed. Ascorbate solution with 1 g/L had an inhibitory effect for the haemoglobin test. Agreement for specific gravity (SG) varied between moderate to substantial, for pondus hydrogenii (pH) was moderate, and for other parameters varied between substantial to excellent, on comparing the results obtained by Hipee S2 with those measured by laboratory reference analysers. The semi-quantitative results of microalbumin and creatinine were highly correlated with the quantitative results. CONCLUSIONS Hipee S2 POCT urine analyser showed acceptable analytical performance as a semi-quantitative method. It serves as a convenient alternate device for clinicians and individual users for urinalysis and health management.

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Correlation of COVID-19 antigen test and CBNAAT results at a single tertiary care hospital in North India: an experience

International Journal of Community Medicine and Public Health ◽

10.18203/2394-6040.ijcmph20211768 ◽

2021 ◽

Vol 8 (5) ◽

pp. 2427

Author(s):

Surbhi Gupta ◽

Anju Shukla ◽

Poonam Singh ◽

Areena H. Siddiqui

Keyword(s):

Tertiary Care Hospital ◽

Point Of Care ◽

Tertiary Care ◽

Uttar Pradesh ◽

Nucleic Acid Amplification ◽

North India ◽

Care Hospital ◽

Antigen Test ◽

Discordant Group ◽

Antigen Tests

Background: Nucleic acid amplification test (NAAT) is considered gold standard in the molecular diagnosis of CoV-2 infection but since it is costly, labor intensive and needs technical expertise, rapid chromatographic immunoassay for the qualitative detection of specific antigens to SARS CoV-2 have been devised. Objectives of this study was to compare the results of Antigen test and NAAT for CoV-2 infection carried out during the months of July and August 2020 by single tertiary care hospital in Lucknow, Uttar Pradesh and to determine the utility of rapid antigen test in the SARS CoV-2 diagnosis.Methods: All the patients who came to our hospital seeking admission during July 2020 and August 2020 were included in the study. A total of 1000 patients were included in this study.Results: Out of a total 1000 cases which were included in the study, 769 cases (76.9%) were found to be SARS CoV-2 negative by both antigen and CBNAAT, 100 cases (10.0%) were SARS CoV-2 positive by both antigen and CBNAAT tests. But in 131 cases (13.1%), antigen was not able to pick up the disease. It was also found that the Cycle Threshold (Ct) value for the discordant group was higher (Mean E= 28, Mean N2=33) when compared to the group where antigen was positive.Conclusions: The present study establishes the role of rapid antigen tests in contributing to the quick, point of care diagnosis of SARS CoV-2. These assays are safe, simple, and fast and can be used in local clinics and hospitals. These tests are very important for real-time patient management and infection control decision.

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