COVID-19 Antigen Rapid Test

MEDsan’s COVID-19 Antigen Rapid Test is a lateral flow antigen test that uses secretion from the nose and throat to determine whether a person is currently infected with the SARS-CoV-2 virus (COVID-19). The test is very accurate and can generate results in 15 to 20 minutes. The test is self-administered and can be completed at home, in an office or any other comfortable setting.

How does the COVID-19 Antigen Rapid Test work?

A MEDsan COVID-19 Antigen Rapid Test works by measuring the presence of COVID-19 antigens in a nose or throat sample. The sample, taken using a sterile swab, is mixed with a buffer solution. The buffer solution encourages the release of any virus fragments from the sample and breaks them down to be absorbed by a strip inside the test device.

The absorbent strip in the test device is lined with a set of labelled antibodies. These antibodies are set to a visible line so we can see their activity and what they interact with. As the sample makes its way down the strip, the labelled antibodies attach firmly to any virus fragments. The virus fragments bound with the labelled antibodies make their way to the test zone.

The test zone possesses a line of fixed antibodies that similarly detect the virus fragments and latch onto them. Any antibodies that do not bind to virus fragments, progress to the control zone at the end of the strip.

A coloured line should appear at the control zone (the letter C on the test device) after around five minutes to signify the test has worked. If a significant number of antibodies are present in the test zone (the letter T on the test device), a coloured line will appear after 15 to 20 minutes. Two coloured lines, one next to the letter C and one next to the letter T connotes a positive test. One line next to the letter C shows a negative test. One line next to the letter T suggests a failed test.

How accurate is a COVID-19 Antigen Rapid Test?

The accuracy of a COVID-19 antigen rapid test can be determined by its sensitivity and specificity. If a COVID-19 antigen rapid test has a high sensitivity, it means the test is very sensitive to COVID-19 antigens and they will easily be detected by the test device. This increases the chance of the test working effectively and producing a result. A rapid test with a high specificity means a false-positive test result is unlikely to occur when the test has been carried out correctly. This improves the validity of the result produced by the test.

A MEDsan COVID-19 antigen rapid test has a sensitivity of 92.5% and a specificity of 99.8%. These figures indicate the test has only a 7.5% chance of not detecting any COVID-19 antigens and a 0.2% chance of producing a false-positive result.

How can employers use antigen tests to protect their workforce?

Protecting the health of the workforce is imperative for many employers. By administering MEDsan COVID-19 Antigen Rapid Tests to employees, employers can accurately and reliably monitor the presence of COVID-19 amongst the workforce.

The test is very simple to conduct and takes little time.

1. A sterile swab is removed from its packaging and inserted into the nostril of the person being tested until it reaches the posterior nasopharynx (this is the area at the back of the nose and above the throat).
2. The swab remains in this position for five to 10 seconds while some secretion is absorbed. The swab is then removed slowly, rotating on its way out.
3. One dose of the buffer solution is added to the extraction tube.
4. The soft tip of the swab is inserted into the extraction tube and mixed with the buffer solution for one minute.
5. As the swab is removed, the outer walls of the extraction tube are squeezed to ensure as much liquid has been extracted as possible. The swab is then discarded.
6. The dispensing tip of the extraction tube is sealed in place.
7. The extraction tube is held vertically and two drops of the solution are added to the well on the test device.
8. After 15 to 20 minutes, a coloured line should appear next to the letter C to confirm the test has been done correctly and is working. A positive test includes a coloured line next to the letter C and a line next to the letter T.

Employers can distribute tests to employees to either be completed at home or in the office. Many institutions, such as schools, encourage testing on school premises during the week and home testing at the weekend.

What is the difference between an antibody test and an antigen test?

Antibody and antigen tests are extremely important in monitoring the impact of COVID-19, but what they find out is very different.

The purpose of an antigen test is to identify the presence of an active COVID-19 infection in an individual at the time of testing. This is crucial as a positive test implies the individual is currently infected with the virus and should take the necessary self-isolation precautions to reduce the spread.

Where an antigen test aims to show whether a person is presently infected with COVID-19, an antibody test identifies whether a person has been infected with the virus previously. An antibody test can also track the presence of antibodies in an individual after a vaccine. Having an understanding of how many people have had the infection in the past is important, particularly when pinpointing people who may have experienced no symptoms.

What is the difference between a lateral flow test and a PCR test?

Lateral flow tests, such as the MEDsan COVID-19 Antigen Rapid Test, and PCR (polymerase chain reaction) tests are both used to detect whether a person is currently infected by a virus. While they are similar in purpose, they do possess some very notable differences.

The examination of a PCR test is usually carried out in a laboratory. PCR tests can test for the virus’ RNA (the genetic makeup of COVID-19). The limitations of PCR tests are the additional financial costs required for the transportation and examination of the tests. This also results in a longer waiting time for results. A PCR test may cost considerably more than a lateral flow test with results taking between one to three days to come through.

In contrast, lateral flow tests do not require examination in a laboratory and can produce a result in a matter of minutes. This also makes them a more affordable option. Unlike the PCR test, lateral flow tests detect proteins from the virus, not RNA.. While they are effective at indicating an active infection, it is generally advised that a positive lateral flow test should be followed up with a PCR test for confirmation.

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