SARS-CoV-2 Rapid Antigen Test Nasal

Reliable, rapid chromatographic immunoassay for the qualitative detection of nucleocapsid antigen present in human nasal samples

SARS-CoV-2 Rapid Antigen Test Nasal
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An aid in identifying individuals infected by SARS-CoV-21

 

The SARS‑CoV‑2 Rapid Antigen Test Nasal is a rapid chromatographic immunoassay for the qualitative detection of SARS‑CoV‑2 nucleocapsid antigen present in human nasal samples.

This test is intended to detect antigen from SARS‑CoV‑2 in individuals suspected of COVID‑19 or with known or suspected exposure to SARS‑CoV‑2. This product is intended for professional use in laboratory and Point of Care environments, or self-collection under the supervision of a healthcare worker.

SARS-CoV-2: An overview of virus structure, transmission and detection

 

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is an enveloped, single-stranded RNA virus of the family Coronaviridae. Coronaviruses share structural similarities and are composed of 16 nonstructural proteins and 4 structural proteins: spike (S), envelope (E), membrane (M), and nucleocapsid (N). Coronaviruses cause diseases with symptoms ranging from those of a mild common cold to more severe ones such as Coronavirus Disease 2019 (COVID-19) caused by SARS-CoV-2 2,3

SARS-CoV-2 is transmitted from person-to-person primarily via respiratory droplets, while indirect transmission through contaminated surfaces is also possible4-7. The virus accesses host cells via the angiotensin-converting enzyme 2 (ACE2) receptor, which is most abundant in the lungs8,9.

The incubation period for COVID-19 ranges from 2 - 14 days following exposure, with most cases showing symptoms approximately 4 - 5 days after exposure4,10,11. The spectrum of symptomatic infection ranges from mild (fever, cough, fatigue, loss of smell and taste, shortness of breath) to critical12,13. While most symptomatic cases are not severe, severe illness occurs predominantly in adults with advanced age or underlying medical comorbidities and requires intensive care. Acute respiratory distress syndrome (ARDS) is a major complication in patients with severe disease. Critical cases are characterized by e.g., respiratory failure, shock and/or multiple organ dysfunction, or failure12,14,15

Definite COVID-19 diagnosis entails direct detection of SARS-CoV-2 RNA by nucleic acid amplification technology (NAAT)16-18. Serological assays, which detect antibodies against SARS-CoV-2, can contribute to identify individuals, which were previously infected by the virus, and to assess the extent of exposure of a population. They might thereby help to decide on application, enforcement or relaxation of containment measures19.

Upon infection with SARS-CoV-2, the host mounts an immune response against the virus, including production of specific antibodies against viral antigens. Both IgM and IgG have been detected as early as day 5 after symptom onset20,21. Median seroconversion has been observed at day 10 - 13 for IgM and day 12 - 14 for IgG22-24, while maximum levels have been reported at week 2 - 3 for IgM, week 3 - 6 for IgG and week 2 for total antibody20-26. Whereas IgM seems to vanish around week 6 - 727,28, high IgG seropositivity is seen at that time20,27,28. While IgM is typically the major antibody class secreted to blood in the early stages of a primary antibody response, levels and chronological order of IgM and IgG antibody appearance seem to be highly variable for SARS-CoV-2. Anti-SARS-CoV-2 IgM and IgG often appear simultaneously, and some cases have been reported where IgG appears before IgM, limiting its diagnostic utility21,22,24,29,30

After infection or vaccination, the binding strength of antibodies to antigens increases over time - a process called affinity maturation31. High-affinity antibodies can elicit neutralization by recognizing and binding specific viral epitopes32,33. In SARS-CoV-2 infection, antibodies targeting both the spike and nucleocapsid proteins, which correlate with a strong neutralizing response, are formed as early as day 9 onwards, suggesting seroconversion may lead to protection for at least a limited time29,34-37.

Coronavirus illustration
  • Nucleocapsid protein (N)
  • Envelope protein (E)
  • Spike protein (S)
  • Membrane glycoprotein (M)
  • RNA

The benefit of having a SARS-CoV-2 antigen test available

 

The SARS-CoV-2 virus causes respiratory tract infection. It is transmitted mainly via respiratory droplets after close contact, and primary viral replication is presumed to occur in mucosal epithelium of the upper respiratory tract (nasal cavity and pharynx).2 At these locations viral load peaks within the first week after symptom onset, and then declines.3

A SARS-CoV-2 antigen test detects the presence of the SARS-CoV-2 virus from part of the upper respiratory tract swab specimens by identifying a nucleoprotein that is carried by the virus. The test identifies current infection during the acute phase of COVID-19, while the virus is still present in large quantities in the respiratory tract.

At Roche Diagnostics we believe wide accessibility to such high-performance, instrument-free and reliable Point of Care tests can contribute significantly to better managing the ongoing pandemic crisis.

 

Features and benefits of the SARS-CoV-2 Rapid Antigen Test Nasal

 

In comparison to the Roche SARS-CoV-2 Rapid Antigen Test, the SARS-CoV-2 Rapid Antigen Test Nasal collects the sample from the front area of the nose instead of the nasopharynx, resulting in a simplified and faster testing procedure.2 This testing method can help reduce overall patient discomfort, particularly in sensitive individuals such as children, elderly people and/or people with disabilities.

Besides being less invasive, the test also provides patients with the option to self-collect their nasal sample under the supervision of a healthcare professional. Through reduced physical contact, this method of testing can help to decrease the risk of exposure to the virus for healthcare professionals. Whether the test could also be used without supervision of a healthcare professional will depend on local regulatory requirements.

 

The benefits of the SARS-CoV-2 Rapid Antigen Test Nasal in short:

 

  • Using a nasal swab for quick and convenient specimen collection
  • Getting a quick result within 15-30 minutes – no need for a follow-up appointment to discuss the result
  • Providing patients with the option to self-collect their nasal sample
  • Allowing decentralized testing or access to testing in areas where laboratory testing is not available
Healthcare professional talking to patient

Testing the quick and easy way

 

Testing process for the SARS-CoV-2 Rapid Antigen Test Nasal1

Collecting the nasal sample from left and right nostril

Testing process

1a.

Insert the sterile swab into the nostril with the most secretion. While rotating the swab, insert the swab 2 cm (slightly less than 1 inch) parallel to the palate (not upwards) towards the throat into the nostril until resistance is met at turbinates. Do not apply pressure. 

Rotate the swab 4 times for about 15 seconds against the nasal wall and remove it from the nostril.

Testing process

1b.

Repeat step 1a. with the same swab in the other nostril.

Note: Samples must be collected from both nostrils using the same swab.

Preparing a sample

Testing process

2a.

Insert the swab into an extraction buffer tube. While squeezing the buffer tube, stir the swab more than 10 times.

Testing process

2b.

Remove the swab while squeezing the sides of the tube to extract the liquid from the swab.

WARNING! Failure to squeeze the tube can lead to incorrect results due to excess buffer in the swab.

Testing process

2c.

Press the nozzle cap tightly onto the tube. Continue with 3a. Performing a test.

Performing a test

Testing process

3a.

Place the test device on a flat surface and apply 4 drops of extracted sample at a 90º angle to the specimen well of the test device.

Testing process

3b.

Read the test result at 15 to 30 min.

WARNING! Risk of incorrect results. Do not read the test result after 30 min.

Interpreting results

Testing process

4.

A colored line appears in the top section of the result window to show that the test is working properly. This is the control line (C). Even if the control line is faint, the test should be considered to have been performed properly. If no control line is visible the test is invalid. 

In case of a positive result, a colored line appears in the lower section of the result window. This is the test line (T). Even if the test line is very faint or not uniform, the test result should be interpreted as a positive result.

Test kit information

 

The kit is ready for use and contains all equipment needed to perform a test.

 

The following components are needed for a test and included in the kit:

  • Test device (individually in a foil pouch with desiccant)
  • Extraction buffer tube and buffer tube rack
  • Nozzle cap
  • Sterile swab
  • Instructions for use and Quick Reference Guide
  • Positive and negative controls
SARS-CoV-2-Antigen-test-nasal-kit
Coronavirus close up

Roche’s response to the COVID-19 pandemic

Our commitment to help put a stop to the COVID-19 pandemic

References

  1. SARS-CoV-2 Rapid Antigen Test Nasal Package Insert 2021-01 V 2.0
  2. Su S, Wong G, Shi W, et al.-Trends Microbiol. 2016;24(6):490–502.-2016-Elecsys Anti-SARS-CoV-2 -L (v1.0)
  3. Zhu, N., Zhang, D., Wang, W. et al.-N Engl J Med 382(8) 727-733-2020-Elecsys Anti-SARS-CoV-2 -Lit (v1.0)
  4. Chan, J.F., Yuan, S., Kok, K.H., To, K.K., Chu, H., Yang, J. et al.-Lancet. 395, 514–523.-2020- El (v1.0)
  5. U.S. CDC. https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/how-covid-spreads.html. Published April 2, 2020. Accessed February 5, 2021. 
  6. WHO. https://www.who.int/news-room/commentaries/detail/modes-of-transmission-of-virus-causing-covid-19-implications-for-ipc-precaution-recommendations. Published March 29, 2020. Accessed February 5, 2021
  7. Kampf, G., Todt, D., Pfaender, S., Steinmann, E.-J Hosp Infect. 104(3), 246–251.-2020- Elecsys Ant (v1.0)
  8. Letko, M., Marzi, A., Munster, V. (2020).-Nat Microbiol. 1–8. doi:10.1038/s41564-020-0688-y.-2020- (v1.0)
  9. Hoffmann, M., Kleine-Weber, H., Schroeder, S. et al.-[published online ahead of print, 2020 Mar 4]. (v1.0)
  10. WHO. https://www.who.int/docs/default-source/coronaviruse/situation-reports/20200403- sitrep-74-covid-19-mp.pdf. Published April 3, 2020. Accessed April 15, 2020. 
  11. Lauer SA et al.-Ann Intern Med 2020;172(9):577-82-The Incubation Period of COVID-19 (v1.0)
  12. Rothe, C et al-N Engl J Med 2020;382(10):970-971-2020-Lab Infectious Diseases Respiratory tract infec (v1.0)
  13. Kupferschmidt K-Science. https://www.sciencemag.org/news/2020/02/paper-non symptomatic-patienttrans (v1.0)
  14. Bai Y et al-JAMA 2020;323(14):1406-1407-2020-Lab Infectious Diseases Respiratory tract infections Co (v1.0)
  15. Mizumoto K et al-Euro Surveill 2020;25(10):2000180.-2020-Lab Infectious Diseases Respiratory tract (v1.0)
  16. WHO. https://apps.who.int/iris/bitstream/handle/10665/331501/WHO-COVID-19- laboratory-2020.5-eng.pdf. Published March 19, 2020. Accessed April 15, 2020. 
  17. U.S. CDC. https://www.cdc.gov/coronavirus/2019-ncov/hcp/clinical-criteria.html. Published March 14, 2020. Accessed April 15, 2020. 
  18. EUCDC. https://www.ecdc.europa.eu/sites/default/files/documents/Overview-rapid-test-situation-for-COVID-19-diagnosis-EU-EEA.pdf. Published April 1, 2020. Accessed April 15, 2020. 
  19. WHO. https://www.who.int/blueprint/priority-diseases/key-action/novel-coronavirus/en/. Published April 11, 2020. Accessed April 15, 2020. 
  20. Liu, W. et al. (2020). J Clin Microbiol. 58(6), e00461-2. 
  21. To, K. et al. (2020). Lancet Infect Dis. 20(5), 565-74. 
  22. Long, Q. et al. (2020). medRxiv. https://doi.org/10.1101/2020.03.18.20038018. 
  23. Lou, B. et al. (2020). Eur Resp J. https://doi.org/10.1183/13993003.00763-2020. 
  24. Zhao, J. et al. (2020). Clin Infect Dis. pii: ciaa344. https://doi.org/10.1093/cid/ciaa344. 
  25. Zhang, B. et al. (2020). medRxiv. https://doi.org/10.1101/2020.03.12.20035048. 
  26. Wölfel, R. et al. (2020). Nature. 581, 465-469. 
  27. Xiao, D.A.T. et al. (2020). J Infect. 81(1), 147-178. 
  28. Tan, W. et al. (2020). medRxiv. https://doi.org/10.1101/2020.03.24.20042382. 
  29. Okba, N. et al. (2020). medRxiv. https://doi.org/10.1101/2020.03.18.20038059. 
  30. Alberts, B. et al. (2002). Molecular Biology of the Cell. 4th edition. New York: Garland Science. B Cells and Antibodies. Available from: https://www.ncbi.nlm.nih.gov/books/NBK26884/ 
  31. Klasse, P.J. (2016). Expert Rev Vaccines 15(3), 295-311. 
  32. Payne, S. (2017). Viruses: Chapter 6 - Immunity and Resistance to Viruses, Editor(s): Susan Payne, Academic Press, Pages 61-71, ISBN 9780128031094. 
  33. Iwasaki, A. and Yang, Y. (2020). Nat Rev Immunol. https://doi.org/10.1038/ s41577-020-0321-6. 
  34. Amanat, F. et al. (2020). Nat Med. https://doi.org/10.1038/s41591-020-0913-5. 
  35. Zhou, P. et al. (2020). Nature. 579(7798), 270-273. 
  36. Haveri, A. et al. (2020). Euro Surveill. 25(11), 2000266. 
  37. Poh, C. et al. (2020). bioRxiv. preprint doi: https://doi.org/10.1101/2020.03.30.015461. 

SARS-CoV-2 Rapid Antigen Test Nasal characteristics

  • Assay format

    Lateral flow test / immunochromatographic

  • Instrument

    No

  • Testing time

    15-30 minutes

  • Specificity

    99.1%

     

     

     

  • Sensitivity

    89.6% (Ct value ≤ 30)

     

  • Antigen

    N

  • Sample material

    Nasal Swab

  • Reagents

    mAb anti-COVID19 antibody, mAb anti-Chicken IgY, mAb anti-COVID-19 antibody‑gold conjugate, Purified chicken IgY‑gold conjugate