Introduction

There are significant differences in quality between antigenic tests for rapid diagnosis. In the Czech Republic, systematic evaluation of the performance of tests (sensitivity and specificity) of antigenic tests has not yet been carried out, except for narrow studies focusing on several selected tests. The overview below is therefore based mainly on foreign evaluations.

WARNING : Although some antigen tests are approved by a number of foreign institutions, it should be noted that PCR tests are currently considered to be the most reliable type of test for COVID-19 . PCR tests, despite their higher cost and longer time required for evaluation, usually provide much greater certainty than the result of a rapid antigen test. Many scientists therefore recommend PCR tests .

Test evaluation

The aim of this page is to provide an indicative overview of the results of the evaluation of selected rapid antigen tests available on the Czech market by other countries and major organizations. The included tests are taken from the “List of antigenic tests for which the Ministry of Health has issued an exemption for use by a lay person”. Thus, the overview does not include antigen tests available on the Czech market outside this list of MH (for example, tests for professional use only).

For the current list of tests positively evaluated by the EU, visit:
COVID-19 In Vitro Diagnostic Devices and Test Methods Database (europa.eu)

If you are interested in previously published test evaluations in partial (national) lists updated to spring 2022, we offer them in the form of a table.

Test evaluation methodology

The table contains the tests listed in the “List of antigen tests for which the Ministry of Health has issued an exemption” (hereinafter referred to as the List of MoHs). The test is identified by a unique combination of test name and manufacturer. If the test was listed more than once on the MoH List (eg for different importers), these records were merged into one. The data on the type of test was also taken over from the Ministry of Health List. For individual tests, it was subsequently ascertained whether the test appeared on any of the monitored public lists issued by selected foreign institutions. The following institutions and lists have been selected:

  • European Union – Common List (Common list) Mutual Recognition List (mutual recognition list)
    • The Czech Republic directly participated in the approval of the lists as a member of the European Commission’s Health Security Committee.
  • Germany – SARS-CoV-2 Test Systems
    • The list maintained by the Paul Erlich Institute is the largest list found in terms of the number of self-evaluated tests that have been successfully evaluated (130).
    • The exact results of the sensitivity assessment according to the Ct (Cq) values ​​were taken from a professional article [23]. This article applies a 75% sensitivity limit for a successfully validated test at Ct <= 25.
    • In some cases, we observed a discrepancy between the results published in the article [23] and the list of SARS-CoV-2 Test Systems, resp. data in the German state database BfArM. Some tests are in Table 2 (unsatisfactory) in [23], but a test from the same manufacturer with a very similar name is either included on the BfaRM positive list (“Eval PEI Ja”) or flagged (“Eval PEI Nein”), which indicates that the test has not been evaluated (although it is on the list of evaluated tests in [23])
  • United Kingdom – List of tests that have been evaluated 3a
    • Testing is performed in the renowned PHE Porton Down laboratory in cooperation with the University of Oxford. In total, over 120 tests were evaluated in the first phase, of which only 30% passed and advanced to the second phase of evaluation. The list shows the tests that have passed phase 3a.
  • USA – List of deleted tests – tests that should not be used or distributed (in the USA)
    • The FDA is internationally recognized for its high standards. No rapid antigen test could be found on the FDA’s positive list, which would be sold in the Czech Republic under the same name. However, the agency also publishes a negative list on which several tests can be found.
  • World Health Organization (WHO) – Emergency Use Listing
    • The Czech Republic is a member of the WHO.
  • FIND – Test directory
    • FIND is a non-profit organization based in Geneva that conducts independent test evaluation. Some EU and WHO documents refer to the evaluation of tests by this organization.
  • Indie – List of Rapid Antigen Test Kits for COVID-19, validated by ICMR
    • The Indian Government Agency ICMR maintains and regularly updates a list of antigen tests that have been evaluated. As of June 28, 2021, India evaluated 118 tests (including revalidations), of which 44 passed.
    • India also publishes a negative list of tests that have been evaluated but have not been evaluated.
  • Czech Republic – The results of a study of antigenic tests were used for the Czech Republic, which were the result of a pilot project implemented by the State Institute of Public Health in Ostrava in the period 26.10.-5.11.2020.

Publication of results

FIS VŠE employees participated in research evaluating antigen tests. The analysis is based on the export of aggregated results of AG and PCR tests registered in the Information System of Infectious Diseases (ISIN) for the period August-November 2021, which was provided to us by the Institute of Health Information and Statistics of the Czech Republic.

The results were published in the article:

Kliegr Tomáš, Jarkovský Jiří, Jiřincová Helena, Kuchař Jaroslav, Karel Tomáš, Tachezy Ruth. Role of population and test characteristics in antigen-based SARS-CoV-2 diagnosis, Czechia, August to November 2021. Euro Surveill. 2022;27(33):pii=2200070. https://doi.org/10.2807/1560-7917.ES.2022.27.33.2200070

Frequently asked questions

The manufacturer states that the sensitivity of the antigen test is close to 100%, is this realistic?

In the Czech Republic, the public could choose from more than a hundred different rapid antigen tests, which were granted an exemption from the Ministry of Health, for self-testing. Although the test importer had to submit a validation study to demonstrate the high quality of the test, the required sensitivity of 90% or higher is rarely confirmed in independent studies (see eg [1, pp. 21-22]). The comparison of tests based on manufacturers’ data is further complicated by the fact that there are no uniform requirements for studies [2, p. 34,43]. Another complication is that manufacturers’ studies have often been conducted outside the European Union, for example in China, where most antigenic tests are manufactured.

Are there differences between brands of antigenic tests?

There are a number of studies available in the scientific literature showing the different quality of tests. For example, a recent Irish government study comparing several tests shows that the real sensitivity of the tests is generally lower than declared by the manufacturer, with the size of the difference varying by brand [1]. Scientific studies have reached similar conclusions (see eg [16,23,24]).

 

Are antigen tests suitable for asymptomatic people?

Evaluations of antigenic tests show that the sensitivity of the tests decreases significantly for asymptomatic individuals. Probably the most extensive study was conducted in the form of 23,463 paired PCR and antigen tests on a population of college athletes in the United States [21]. The study used an antigen test from Quidel, who also funded the study.

  • Antigen test sensitivity in asymptomatic athletes 35.7%
  • The tests were performed by certified personnel after training
  • Daily testing did not prevent two outbreaks
  • A feeling of false security after a negative test may have contributed to this
  • The authors state that even during daily testing, it is necessary to apply airway obstruction and distances

For the Korean Abbott Panbio test, which is probably the test with the highest number of approvals across selected institutions, an Irish government study found a sensitivity of only 51.9% for asymptomatic cases [1]. Thus, the test revealed only about half of the infected people. Another study using the Innova test, which is made in China and is used for field testing in the United Kingdom, found only 3% of infected asymptomatic students [2, p. 42]. A US CDC study states that 59% of infected asymptomatic students passed another antigenic test (sensitivity 41%) [19].

Are asymptomatic individuals contagious?

According to estimates cited by the US Centers for Disease Control (CDC), over 50% of transmissions occur from individuals who are either pre-symptomatic or asymptomatic [5, 6].

Are antigen tests suitable for people with low viral loads?

The Paul Ehrlich Institute of Germany states that the sensitivity of antigen tests is an order of magnitude lower than that of PCR tests. According to this authority, this type of test makes sense for people with a high viral load. According to the same source, high load is associated with a period of 1-3 days before the onset of symptoms and an early symptom period of 5-7 days after the onset of symptoms [9].

Are people with low viral infections contagious?

Many authoritative studies say yes. These include the report by the Health Services Ireland [1] and the Royal Statistical Society (United Kingdom) [2]. The latter states that the infectious virus can be cultured from one third of the samples with a low viral load (Ct> 25).

How does the sensitivity of antigenic tests change when used in children?

Most studies were performed in the adult population. Two studies with sufficiently large samples of children were found.

Children in the Swiss study [7] found that the tests were less sensitive than adults:

  • In the case of asymptomatic children, a sensitivity of 43% was found,
  • In the case of symptomatic children, a sensitivity of 73% was found.
  • Less sensitivity was found when testing children under 12 years of age (than in older children).
  • The results shown are for the Panbio test (Abbott Diagnostics, Ltd. Korea)

Similar results were found in another US study [20]:

  • In the case of asymptomatic children, the sensitivity was 57.1%.
  • In the case of symptomatic children, the sensitivity was found to be 75.9%.
  • Less sensitivity was found in testing children than adults.
  • The results shown are for the BinaxNOW test (Abbott Diagnostics, Ltd. Korea) *.
  • In this study, asymptomatic cases were predominantly in the pre-symptomatic phase and not in the recovery phase.

The results found in Mexico [22] confirm worse results in children than the average in this study:

  • Symptomatic children aged 0-13: 35.9%
  • Symptomatic children aged 14-17: 37.1%
  • The results shown are based on the results of several types of tests approved in Mexico. The tests used include a test by the manufacturer Genrui, which also supplied tests to schools in the Czech Republic.

* According to the manufacturer’s website, the BinaxNOW and Panbio tests have a similar biological basis. BinaxNOW is used in the USA and Panbio in Europe.

Is nasal or nasopharyngeal sampling more reliable?

A study comparing nasopharyngeal sampling with nasal sampling for rapid antigen tests conducted by FINDX reported a 4.5% decrease in sensitivity from nasopharyngeal sampling. The result is for the Panbio test (Abbott Diagnostics, Ltd. Korea) [8]. Other studies report comparable results for both sampling methods [12].

Is saliva or oral pharyngeal sampling reliable?

A very limited number of independent studies are available for these sampling methods. The European Disease Control Center (ECDC) saliva test report states that the suitability of saliva sampling for rapid antigen tests is not supported by the available data [17]. Based definitely by three experts of the HSC EU from July 6, 2021 will salivary tests included on the list of common ( “Common List”) [18]. 

The problematic results of these tests are indicated by the fact that the Indian regulator lists 9 unapproved rapid antigen saliva tests, but not a single approved test [15]. Recommendations for antigen testing in the US also do not envisage that samples for antigen testing should be taken other than from the nasopharynx or the nose [11].

Despite the above results, tests have been approved in the Czech Republic that use methods of collection other than from the front of the nose or nasopharynx. These tests use saliva obtained from the oral cavity obtained by swabbing, sputum, or stool. These tests were approved on the basis of validation studies provided by the manufacturers (importers), according to which the tests achieve a clinical sensitivity of 90% or higher. Some studies even declare a sensitivity of 100%. In a recently published meta-analysis, however, saliva samples reached the lowest aggregate sensitivity of all sample types – only 37.9% [12].

Sample type Sensitivity N (number of samples)
Nasopharynx (or nasopharynx + oropharynx) 71,6 % 59 810
Front or middle part of the nose 75,5 % 25 814
Oral pharynx (oropharynx) 53,1 % 5 165
Spit 37,9 % 1 088

Sensitivity of rapid antigen tests depending on the method of collection. Source: [12]

It follows from the above that the results of independent scientific studies are in clear contradiction with the declared sensitivity of manufacturers (importers). In the case of stool tests, no large-scale metastudy [12] mentions any study focusing on this type of test.

What is the effect of the expertise of the person carrying out the test on the test result?

The following table illustrates the difference in test sensitivity based on who performs the test [10].

Experience of the person carrying out the text
Government study verifying the quality of rapid antigen tests – United Kingdom
The test is performed by a trained healthcare professional 70.0 % 156 of 223 correctly marked as positive
The test is performed by a self-trained member of the public based on a protocol 57.5 % 214 out of 372 correctly marked as positive

Test data Innova SARS-CoV-2 Antigen Rapid Qualitative Test. Source: [10]

Do individual institutions apply the same stringent criteria when assessing

Test evaluation methods vary between institutions. E.g. in the Czech Republic, the exemption required the test to reach a clinical sensitivity of 90% or higher, while the WHO, for example, requires 80%, and in India the requirements are even lower. However, despite the seemingly stricter requirements, there are more approved tests in the Czech Republic than, for example, in India. The probable reason is that in the Czech Republic it is sufficient for the stated value to be stated in a clinical study supplied by the importer, while other states and organizations carry out their own evaluation of tests.

The actual self-assessment carried out by foreign organizations also differs. Some types of evaluations use real samples, others are based on an analytical method, where a known concentration of analyte (viral antigen) is artificially introduced into the sample (a so-called spiked sample is created). Sometimes both methods are combined. The report of the Royal Statistical Society (United Kingdom) states that evaluation based on an analytical method may show significantly different results compared to the use of real samples [2, p. 39] .

Interesting. The report of the Royal Statistical Society cites as an example the Abbott ID-NOW test, which showed 100% sensitivity in the FDA evaluation based on the analytical method. The test was then used to test participants in the White House Rose Garden, which infected 31 participants, including President Donald Trump. Subsequent analysis of the test on real data showed that the estimated real sensitivity of the test is only 73% [2, p. 34].

News

April 5, 2022. Updated data

January 20, 2022. Updated data.

January 10, 2022. Updated data.

December 2, 2021. Beta version of English language mutation of COVID testy launched.

December 1, 2021 . Updated data to the version of the EU Common List issued on 10 November 2021, updates were also made to other lists.

November 28, 2021. Added experimental support for displaying accurate sensitivity in PEI study tests [23].

November 25, 2021. Added a study [22] confirming the low sensitivity of antigenic tests, especially in children.

November 10, 2021. New version of the Common List published .  Changes to this version are not yet reflected in covidtesty.vse.cz.

9 November 2021. The list takes into account the new version of the Common List of 20 October 2021.

October 20, 2021. The EU issued another version of the Common List . A new distinction is made between tests for which there are only in vitro studies and tests for which a clinical study is available.

August 19, 2021: Added results of other scientific studies.

July 21, 2021 : Batist Medical won the school test contract. The Czechia will pay 19 crowns for one antigen test

Note In Germany, retail prices for cheaper antigen tests are around CZK 20, eg here for 85 cents or here for 80 cents.

July 15, 2021: A  scientific study is published showing that daily antigen tests have not been able to fully prevent the transmission of Sars-Cov-2 among college athletes. Paired use of antigen and PCR tests revealed a total of 21 positive individuals, of which only 3 (14%) were detected by antigen test, the remaining 18 (86%) tested negative.

July 14, 2021 : The European Union updates the Common List . Tests from sampling methods other than the nose, oropharynx and nasopharynx were excluded as part of the update. Therefore, tests from saliva, sputum or stool are not included.

June 25, 2021 : The Ministry of Education, Youth and Sports published a procedure for antigen testing in schools (since September).

June 2021: The Royal Statistical Society issues an extensive 90-page report on diagnostic tests for COVID-19. https://rss.org.uk/policy-campaigns/policy-groups/working-group-on-diagnostic-tests/

June 10, 2021: The US Drug Administration (FDA) withdrew the Innova test, among other reasons, because the manufacturer’s test characteristics did not represent the results of clinical trials . This is the main test used in the United Kingdom, where the government has spent £ 2.8 billion on this test .

June 4, 2021: The Irish Government’s Antigen Test Evaluation Group issued a set of recommendations based on its own test evaluation .

  • Only one of the evaluated tests had a sensitivity of over 90%.
  • The group identifies with the unsuitability of saliva for rapid antigen tests due to significantly lower sensitivity.
  • The main conclusion: The quality of rapid tests varies greatly, they should not be interchangeable .

3 May 2021: The European Center for Disease Control issues a report on saliva testing. The report states that current studies do not support the suitability of saliva collection for rapid antigen or antibody tests.

April 20, 2021: One of the first studies quantifying the sensitivity of rapid antigen tests in children is published .

  • In the case of asymptomatic cases the sensitivity is 43%, in the case of higher viral load 86% .
  • Less sensitivity in children under 12 years of age.
  • The results are for the Abbott Panbio test (South Korea).

Resources

  1. Health Service Ireland. COVID-19 antigen test validation summary report. https://www.hse.ie/eng/services/news/newsfeatures/covid19-updates/covid-19-antigen-test-validation-summary-report.html [2. července, 2021]
  2. Royal Statistical Society Diagnostic Tests Working Group, Report JUNE 2021. https://rss.org.uk/policy-campaigns/policy-groups/working-group-on-diagnostic-tests/
  3. Comparative evaluation of the sensitivities of SARSCoV-2 antigen rapid tests. 25.6.2021 https://www.pei.de/SharedDocs/Downloads/EN/newsroom-en/dossiers/evaluation-sars-cov2-antigen-tests-overview-04-12-2020.pdf
  4. EU health preparedness: A common list of COVID-19 rapid antigen tests, including those of which their test results are mutually recognised, and a common standardised set of data to be included in COVID-19 test result certificates. https://ec.europa.eu/health/sites/default/files/preparedness_response/docs/covid-19_rat_common-list_en.pdf [2. července, 2021]
  5. Evaluation of Abbott BinaxNOW Rapid Antigen Test for SARS-CoV-2 Infection at Two Community-Based Testing Sites — Pima County, Arizona, November 3–17, 2020. https://www.cdc.gov/mmwr/volumes/70/wr/mm7003e3.htm?s_cid=mm7003e3_w
  6. Moghadas SM, Fitzpatrick MC, Sah P, et al. The implications of silent transmission for the control of COVID-19 outbreaks. Proc Natl Acad Sci U S A 2020;117:17513–5.
  7. L’Huillier, Arnaud, et al. „Diagnostic accuracy of SARS-CoV-2 rapid antigen detection testing in symptomatic and asymptomatic children in the clinical setting.“ medRxiv (2021). https://www.medrxiv.org/content/10.1101/2021.04.15.21255577v1
  8. FIND Evaluation of Abbott. Panbio COVID-19 Ag Rapid Test Device (NASAL). External Report Version 1.0, 11 February 2021 https://www.finddx.org/wp-content/uploads/2021/02/Panbio_Nasal_Ag-Public-Report_20210211v1.pdf
  9. Paul Ehrlich Institute. Minimum criteria for SARS-CoV-2 antigen tests within the meaning of Section 1, Paragraph 1, Clause 1 of the TestVO: Rapid antigen tests. June 11, 2021 https://www.pei.de/SharedDocs/ Downloads / DE / newsroom / dossiers / minimum-criteria-sars-cov -2 -antigentests-01-12-2020.pdf? __blob = publicationFile & v = 6
  10. Team, Lateral Flow Oversight, and Tim Peto. „COVID-19: Rapid Antigen detection for SARS-CoV-2 by lateral flow assay: a national systematic evaluation for mass-testing.“ medRxiv (2021). https://www.medrxiv.org/content/10.1101/2021.01.13.21249563v2
  11. Interim Guidance for Antigen Testing for SARS-CoV-2. Updated June 14, 2021. https://www.cdc.gov/coronavirus/2019-ncov/lab/resources/antigen-tests-guidelines.html
  12. Bruemmer, Lukas E., et al. „The accuracy of novel antigen rapid diagnostics for SARS-CoV-2: a living systematic review and meta-analysis.“ medRxiv (2021). https://www.medrxiv.org/content/10.1101/2021.02.26.21252546v1
  13. Antigen Template for Test Developers. FDA. https://www.fda.gov/media/137907/download
  14. List of Rapid Antigen Test Kits for COVID-19, validated by ICMR https://www.icmr.gov.in/ckitevaluation.html [dokument z 28.6.2021]
  15. List of companies / vendors of Saliva Based Rapid Antigen test kits for COVID-19 validated / being validated by ICMR. https://www.icmr.gov.in/ckitevaluation.html [dokument z 3.5.2021]
  16. Dinnes, J., Deeks, J. J., Berhane, S., Taylor, M., Adriano, A., Davenport, C., … & COVID, C. (2021). Rapid, point‐of‐care antigen and molecular‐based tests for diagnosis of SARS‐CoV‐2 infection. Cochrane Database of Systematic Reviews, (3).
  17. Considerations for the use of saliva as sample material for COVID-19 testing. Technical Report. ECDC. 3.května 2021. https://www.ecdc.europa.eu/en/publications-data/considerations-use-saliva-sample-material-covid-19-testing
  18. EU health preparedness: A common list of COVID-19 rapid antigen tests and a common standardised set of data to be included in COVID-19 test result certificates. This document was agreed by the HSC on 17 February 2021. A fourth update was agreed by the HSC on 14 July 2021 . https://ec.europa.eu/health/sites/default/files/preparedness_response/docs/covid-19_rat_common-list_en.pdf
  19. Pray, Ian W. „Performance of an antigen-based test for asymptomatic and symptomatic SARS-CoV-2 testing at two university campuses—Wisconsin, September–October 2020.“ MMWR. Morbidity and mortality weekly report 69 (2021).
  20. Ford, Laura, et al. „Characteristics of children and antigen test performance at a SARS-CoV-2 community testing site.“ medRxiv (2021).
  21. Harmon, Kimberly, et al. „Surveillance testing for SARS-COV-2 infection in an asymptomatic athlete population: a prospective cohort study with 123 362 tests and 23 463 paired RT-PCR/antigen samples.“ BMJ Open Sport & Exercise Medicine 7.2 (2021): e001137.
  22. Murillo-Zamora, Efrén, et al. „Performance of Antigen-Based Testing as Frontline Diagnosis of Symptomatic COVID-19.“ Medicina 57.8 (2021): 852. https://www.mdpi.com/1648-9144/57/8/852/htm
  23. Scheiblauer, Heinrich, et al. „Comparative sensitivity evaluation for 122 CE-marked rapid diagnostic tests for SARS-CoV-2 antigen, Germany, September 2020 to April 2021.“ Eurosurveillance 26.44 (2021): 2100441. https://www.eurosurveillance.org/content/10.2807/1560-7917.ES.2021.26.44.2100441
  24. Puyskens, Andreas, et al. „Establishment of a specimen panel for the decentralised technical evaluation of the sensitivity of 31 rapid diagnostic tests for SARS-CoV-2 antigen, Germany, September 2020 to April 2021.“ Eurosurveillance 26.44 (2021): 2100442.

Contact

The author of the web content is doc. Ing. Tomáš Kliegr, Ph.D. Expert consultation of web content – RNDr. Ruth Tachezy, Ph.D.   Web design Ing. Stanislav Vojíř, Ph.D. Obtaining data from foreign lists – VŠE students .

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    Disclaimer

    The information and materials provided on this site are for informational purposes only and are offered in good faith. The authors believe that this information is valid at the time of publication. We make no representations or warranties regarding the adequacy, reliability, completeness or accuracy of the information contained in this material and accept no liability for any inaccuracies or incompleteness of the content.

    Acknowledgment

    The creation of this overview is partially supported by the CIMPLE project (CHIST-ERA-19-XAI-003).

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