Doctor wearing a white mask and a blue glove holds a small white rapid antigen test against a blue backdrop

Everything You Need to Know About the Novel Coronavirus Rapid Antigen Test

Countries around the world have adopted COVID-19 rapid antigen tests to complement the standard polymerase chain reaction (PCR) test and other public health measures. However, Australia is only just introducing this second level of testing for personal, at-home use.

Australian Health Minister Greg Hunt is pushing for rapid antigen tests to be available for home use by Christmas this year. But they need to be approved first by the Therapeutic Goods Administration (TGA).

The tests will allow Australians to test themselves for the SARS-CoV-2 virus in the comfort of their homes and obtain results within half an hour. This convenience may encourage more people to get tested since they no longer have to wait in clinic lines for hours on busy days. It’s important to know that this at-home test should not replace the PCR test. If you receive a covid-positive result, you should immediately get tested again at a clinic and self-isolate.

Here is everything you need to know about the COVID-19 rapid antigen test.

What is a rapid antigen test and how does it work?

Close up of a person’s hands holding a rapid antigen test and using a pipette to drop a liquid into it
Image Source: istock via The Irish Times

Antigen tests are a fast and simple way to identify a specific antigen. An antigen is any foreign substance in the body, like a virus or bacteria. Antigen tests existed long before coronavirus rocked the world. For example, flu and strep throat both have rapid antigen tests that can quickly be done in the doctor’s office with results after 15 minutes.

The tests bear similarity to at-home pregnancy test kits. For the COVID-19 antigen test, you take a throat swap and put it on a treated strip. The strip then uses a colour or marker to show you whether coronavirus is present.

Graphic illustration of a red coronavirus cell with white antigens on its surface and blue cells in the background
Image Source: Sergii Iaremenko/Science Photo Library via Getty Images

The antigen test works by isolating a unique part of the virus, such as a specific protein on one of its ‘corona’ spikes. If that particular protein exists in detectable quantities, then the test returns a positive result. You do not have to have any COVID-19 symptoms to test for the virus.

How is rapid antigen testing different to other tests?

A gloved hand holds a rapid antigen test with its packaging laid out on the table below it
Image Source: kiweno.com

The rapid antigen test is a screening test that people can use to identify positive cases earlier on in the virus’ infectious period. This early identification can help limit the spread of coronavirus and prevent mass outbreaks.

Alternatively, the standard polymerase chain reaction (PCR) test is a diagnostic test. It can confirm if you have COVID-19 with results usually available in 24 hours. These tests take a deep nasal and throat sample and are tested in laboratories.

Person wearing a face shield and blue gloves takes a swab from a girl’s nose
PCR Test / Image Source: gavi.org

Caution: A positive rapid antigen test result may not necessarily mean you have the virus. If the rapid test returns a positive result, you must get a PCR test immediately to confirm the results.

Accuracy rate

Three rapid antigen tests arranged side by side on a blue surface
Image Source: Marco Verch (CC BY 2.0)

Rapid antigen tests can detect most COVID-19 cases. However, they are not as accurate as the gold-standard PCR test. Therefore, it’s crucial you use the rapid test as an indicator but not as confirmation. If you develop symptoms or are a close contact with someone who has coronavirus, immediately get a PCR test at a clinic and self-isolate.

Benefits of rapid antigen testing

Close-up of a corona quick test at home. The bar at the "C" shows a negative result.
Image Source: racgp.org.au

Rapid antigen tests have been used overseas to screen employees for COVID-19 (including those with no visible symptoms). This allows for earlier detection of the virus if it is present and significantly reduces its spread.

The tests can be performed quickly and easily, with results obtained within minutes. They also use less invasive nose and mouth swabs than the PCR tests.

Despite these benefits, the rapid antigen tests may not be as accurate as the PCR test. So, it’s essential to follow a positive antigen test with a further clinical test at a COVID-testing clinic.

Who can access rapid antigen testing?

Employers, schools, industries and government agencies have all employed rapid antigen testing onsite. The TGA has published check listed advice for businesses to help them safely implement the rapid testing into their workplaces. Research to aid in more detailed guidance for COVID-19 testing in workplaces is currently underway in the Commonwealth Department of Health.

The TGA also announced its pending regulations to allow companies to supply self-tests for people to use at home legally. This home use will be available in Australia from November 1st this year.

Woman sits at kitchen table with a rapid antigen test kit laid out in front of her
Image Source: bioworld.com

The TGA is working with manufacturers and suppliers of rapid self-tests to ensure that instructions are clear and written in a way that all consumers can understand.

In a statement, the TGA said any rapid antigen tests approved for at-home use would be accompanied by simple-to-use instructions, fact sheets and a supporting phone helpline or explainer video.

Where can you get a rapid antigen test in Australia?

Woman wearing a mask sits at a table with a rapid antigen test laid out on the table in front of her
Image Source: australianageingagenda.com.au

Rapid-antigen tests are already being used in some settings across Australia, such as aged care homes and some quarantine facilities and workplaces. The TGA has currently approved 33 rapid tests for use under supervision. From the 1st of November, some testing kits will be available for at-home use.

Once the rapid antigen tests are approved for at-home use, they will be available from local supermarkets like Coles and Woolworths.

How much do the tests cost?

The rapid testing kits are likely to cost between $10-$30. Most stocking stores will sell them in packs of two or five online and in-store.

Who can perform a rapid antigen test?

Woman takes her own nose swab sample while looking in a mirror
Image Source: Ellen Moran via Getty Images

Currently, the TGA requires rapid antigen tests to be administered by trained staff who can use the device correctly and accurately interpret the results. Suitably trained staff can perform the test if supervised by a health practitioner, either in person or via video. Staff can perform tests if a health practitioner monitors them in person or over video.

From November 1st 2021, the TGA will enforce new regulation that permits companies to supply their self-tests for at-home use in Australia legally.

What to do with your results

The test will return either a positive or negative result (or invalid).

An infographic shows positive, negative and invalid rapid antigen test results
Image Source: humimmu.com

Positive result

If the antigen test returns a positive result for COVID-19, you must do two things:

  1. Immediately get a standard (PCR) COVID-19 test at a testing clinic to confirm the screening test results
  2. Self-isolate until you receive a negative result

The purpose of the rapid antigen test is to alert you to the virus’ presence earlier on so you can isolate and avoid infecting others.

Negative result

Continue to follow the latest health advice in your area. If you develop any symptoms at any stage, get a PCR COVID-19 test and isolate while waiting for a negative result.

Concerns about the rapid antigen test

A man’s hand holds a rapid antigen test in front of a COVID-19 information sheet
Image Source: Shutterstock

One of the main shortcomings of these tests is their high tendency to return false-negative results. In other words, you may have COVID, but the rapid antigen test might not pick it up. On the other hand, false-positive results (i.e., results showing a healthy person infected with the virus) are very rare.

However, false-positive errors still exist in antigen tests due to technical issues such as incorrect handling or contamination. These issues are worrying because they can result in adverse health effects for people who test positive (but are not). For example, they could be quarantined with active COVID-19 people or receive medication treatments that might otherwise be harmful.

In the U.S., the Food and Drug Administration (FDA) released a warning letter to remind clinical staff and healthcare providers about the dangers of false-positive and false-negative results from rapid antigen tests.

While these concerns about false results are warranted, the Australian Health Minister reminds us that the antigen tests are supposed to complement, not replace, PCR testing. So even where accuracy is questioned, a PCR test will always be available to double-check.

Concerns about access

In the U.S., making the COVID-19 vaccine free and easily accessible significantly reduced cases in the spring of 2021. At-home antigen tests are currently not free. But similar to the free vaccine, making frequent rapid testing accessible could help stifle case numbers. However, the problem is that the tests require multiple repetitions (unlike the two-dose vaccine), and distributing one free test per person would not be enough.

Coles and Woolworths to sell rapid antigen tests in Australia

A collaged image of Coles and Woolworths supermarkets and a man holding a rapid antigen testing kit
Image Source: Daily Mail

Supermarkets Coles and Woolworths have confirmed they will stock rapid antigen tests from November 1st in stores across New South Wales and Victoria. Currently, Woolworths says the Hough Covid-19 Home Tests will not be shipped to Western Australia or South Australia due the state government regulations.

Coles confirmed that around 700 stores would stock the 15-minute test kits. The kits will be ‘available for sale at Coles supermarkets and via Coles Online in Victoria, New South Wales, Queensland, Northern Territory, the ACT and Tasmania.’

Customers can already pre-order at-home tests from Woolworths’ digital health and wellness business Healthy Life.

Instructions: How to use the Hough COVID-19 rapid antigen test at home

 A white cardboard box containing Hough rapid antigen tests
Image Source: broadsheet.com.au

You can find detailed instructions (including images) on using the Hough COVID-19 home tests here.

Step 1

Before starting to test, wash or sanitise your hands and make sure they are dry. You must use the test within seven days of the onset of symptoms.

Empty the box and pop out the extraction tube holder.

Step 2

Break the tip of the single-use vial with the extraction buffer.

Step 3

Pour all the extraction buffer inside into the extraction tube.

Step 4

Remove the swab from the pouch. Do not touch the swab tip.

Step 5

Gently insert the swab up to 1-2 centimetres into the nostril. Roll the swab around the inside wall of both nostrils at least 4 times. Note: False negatives may occur if the nasal swab is not collected correctly.

Step 6

Insert the swab into the extraction tube and swirl the swab about 5 times while submerged to mix the sample vigorously in the buffer.

Step 7

Squeeze out as much liquid as possible from the swab by pinching the side of the flexible extraction tube. Press the cap tightly onto the extraction tube.

Step 8

Remove the test cassette from the foil pouch and place the test cassette on a flat surface. Apply 4 drops of extracted sample to the sample well of the test cassette. Dispense the sample at 90 degrees to allow for free-falling drops and avoid bubbles.

Step 9

After 15 minutes of development time, illuminate the result window with a UV flashlight to observe the test result.

Step 10

Dispose of used swab and cassette in the trash. Ensure you wash your hands thoroughly

Result interpretation

Positive: If a visible red fluorescent band appears in the test region and the control region at the same time, the test is SARS-CoV-2 N protein-positive. (A faint line is still an Indication of a SARS-CoV-2 N Protein Positive.)

If your result is positive, you must immediately self-isolate, contact the authorities in your state or territory, and arrange a laboratory PCR test.

Negative: If a red fluorescent band becomes visible in the control region and no visible red fluorescent band in the test region, the test is SARS-CoV-2 N protein negative.

Negative results may not mean that a person is COVID-negative. If symptoms are present, you should arrange to have a laboratory PCR test.

Invalid: If there is no visible red fluorescent band in the control region, regardless of whether there is a red fluorescent band in the detection area, the test result is invalid. The sample needs to be tested again with a new test cassette.

Important note: Many home tests advise testing twice over three days with at least 36 hours between tests. Rapid antigen tests work best when testing is done regularly.

Before travelling

Man holding luggage at the airport stands next to a yellow COVID-19 testing direction sign
Image Source: usnews.com

Most airlines and countries have different requirements for COVID-negative proof before you are allowed to travel. These requirements will differ depending on where you come from and where you are going. Therefore, it’s important to check the airline’s regulations and your destination location before embarking on your journey. In most cases, you will be required to present a negative PCR test before taking a flight. A rapid antigen test alone may not be sufficient. However, in some instances, airlines may ask you to take a rapid antigen test and provide a negative result immediately before your flight as part of their risk management process.

Ultimately, the rapid antigen test will help slow the spread of COVID-19 by allowing people to identify earlier in the infectious period if they have the virus. The rapid test is not intended to replace the standard PCR test. Rather, it should be used as a precursor to any further testing needed.

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