COVID-19 Antigen Rapid Test
Find out how the test works.
COVID-19 Antigen Rapid Test is a rapid assay for the qualitative detection of SARS-CoV-2 antigens in nasopharynx specimens. Intended for professional use only.
Are you interested in buying our COVID-19 Antigen Rapid Test kit? Please write to firstname.lastname@example.org for further information.
Principle of the Test
COVID-19 Antigen Rapid Test is a rapid membrane-based lateral flow immunoassay for the qualitative detection of SARS-CoV-2 antigens in human nasopharyngeal swab specimens. During testing SARS-CoV-2 antigens possibly present in the specimen react with the antibody-coated nanoparticles present in the test. The resulting complex chromatographically migrates upward in the strip membrane by capillary action.
If the specimen contains SARS-CoV-2 antigens, they will bind to the SARS-CoV-2 antibodies coated on the (T) Test line region and generate a colored line on the test strip, indicating a positive result. If the antigens are not present in the specimen, no colored line will appear in the (T) Test line region, indicating a negative result. As a procedural control, a colored line will always appear in the (C) Control line region, indicating that the test procedure has been performed properly and that test components have operated as intended.
COVID-19 Antigen Rapid Test is dedicated to healthcare professionals with the aim to support them in the COVID-19 emergency management, receiving quick answers about the health status of their patients:
- high Sensitivity and Specificity standards, when compared to a PCR Methodology;
- safe and accurate results in just 15 minutes;
- easy to use and to read.
Why using a COVID-19 antigen test?
The use of a COVID-19 Antigen Rapid Test allows to detect the presence of SARS-CoV-2 virus antigens in our body and to take initial precautionary isolation measures in order to reduce further spread of the virus.
As stated by Mina et al. in the New England Journal of Medicine, as a result of the increase or stabilisation of COVID-19 cases in most parts of the world, there is a growing need for diagnostic devices that are accurate and sensitive, easy to use and with a quick turnaround time, in order to allow frequent testing operations. Tests, having such characteristics and similar to the PCR technique, have been developed, in order to facilitate the diagnosis and traceability of newly infected people: the antigen tests.
Since the transmission of SARS-CoV-2 virus seems to occur days after exposure to it, when the viral load reaches its peak, the frequency of testing operations is increasingly important in order to slow down the spread of the pandemic, as shown in Figure 1.
The criteria expressed in Figure 1 could be defined as a surveillance method, intended to reduce the population prevalence of SARS-CoV-2 and return results quickly, in order to limit asymptomatic spread. This surveillance approach cannot be performed using the standard PCR technique because, after collection, PCR samples usually require transport to specialised laboratories run by experts, this in turn requires one or more days for the results, creates a bottleneck and is expensive.
This is why the need for highly sensitive and specific tests such as the antigen tests, which open the door to effective population-wide monitoring.
How does the Test work?
A) Sample collection: insert the sterile swab through the nostril parallel to the palate, until the contact with the nasopharynx. Gently rub and roll the swab and take it out from the nasal cavity;
B) Insert the swab into the extraction buffer and rotate it for about 10 seconds. Remove the swab while squeezing the sides of the tube in order to extract as much liquid as possible;
C) Add 3 drops of the extracted specimen to the sample well. Wait 15 minutes and read the results. Once 20 minutes have elapsed the results should no longer be read.
Positive Result: Two coloured lines appear. A coloured line should always appear in the Control (C) region and another line should be in the Test (T) region. Positive result indicates detection of SARS-CoV-2 antigens in the sample.
Negative Result: A coloured line appears in the Control (C) region. No line appears in the Test (T) region.
Invalid Result: The control line does not appear. Insufficient diluent volume or incorrect procedural techniques are the most likely reasons for the absence of the control line. Review the procedure and repeat the test with a new device. If the problem persists, discontinue the use of the test kit immediately and contact your local distributor.
COVID-19 Antigen Rapid Test will only indicate the presence of SARS-CoV-2 antigens in the specimen and should not be used as the sole criteria for the diagnosis of SARS-CoV-2 infections. The results obtained with this test should be considered with other clinical findings from other laboratory tests and evaluations.
1. European Centre for Disease Prevention and Control, Disease background of COVID-19 (https://www.ecdc.europa.eu/en/2019-ncov-background-disease)
2. WHO Director-General’s opening remarks at the media briefing on COVID-19 - 11 March 2020 (https://www.who.int/dg/speeches/detail/who-director-general-s-opening-remarks-at-the-media-briefing-on-covid-19---11-march-2020)
3. Centers for Disease Control and Prevention, Interim Guidelines for Collecting, Handling, and Testing Clinical Specimens for COVID-19 (https://www.cdc.gov/coronavirus/2019-ncov/lab/guidelines-clinical-specimens.html)
4. Mina M.J., Parker R., Larremore D. B., “Rethinking Covid-19 Test Sensitivity — A Strategy for Containment”, NEJM, 2020, doi: 10.1056/NEJMp2025631 https://www.nejm.org/doi/full/10.1056/NEJMp2025631