Rapid Coronavirus Tests: Are They Accurate?

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For the past seven months, the world has been subjected to one of the largest health crises known to man: the COVID-19 pandemic. According to recommendations made by the Center for Disease Control (CDC), some effective ways to stop the spread of this deadly disease are to quarantine for 14 days after any high risk exposure to the virus and to maintain a safe social distance from others. As restrictions have begun to ease, the world is attempting to reopen and to create a sense of normalcy. COVID-19 tests have become one of the most sought-after products in today’s medical world. These tests are crucial; they determine whether someone is infected with the virus or not. As of now, two tests are available, and they fall into two categories: the diagnostic test and the antigen assays test, also known as the rapid test. Although an increasing number of people are using rapid coronavirus tests to screen for the virus, they are not entirely accurate. 

The rapid test provides results in less than fifteen minutes and is administered by swabbing one’s nasal cavity. It is certainly less invasive than the diagnostic test, which is administered by blood test, and its results often take up to five days to appear. These tests are much cheaper than the antibody tests. They can detect specific proteins on the surface of the virus and identify people who are at the peak of their infection. The federal government recently purchased 150 million new coronavirus rapid tests. Although these tests offer quicker results, are less invasive, and are more readily available, how accurate are they?  The rise in the use of the rapid COVID-19 test has led to a debate about whether the tests and results are truly accurate.  

According to the article “Which Test Is Best for Covid-19?” posted on Harvard Health Blog, there are a variety of reasons the rapid COVID-19 tests are not completely accurate, including the methods of collection, contamination during collection, poor sample type, and ineffective reading of results. The tests involve the collection of bodily fluids using a nasal swab, which is then mixed with a few milliliters of a buffer solution. Drops are then spotted on one end of a test strip. If the antibodies spot their target, the test strip will generate a color change, indicating a positive test. The challenge is trying to find the right antibodies. The test does not build up the protein indicator itself, making it less sensitive. When the indicator is diluted with the liquid that allows flow to the test strips, the result is a sensitivity of anywhere between 50% and 90%. One in two infected people might receive a false negative. The rapid test was able to correctly identify the virus in 95-100% of the cases if the samples were collected within a week of the onset of symptoms. Results drop to 75% if samples were taken more than a week after people first showed symptoms (health.harvard.edu). 

Some tests yield false negatives when an infected person is said to be free of the virus, not because of poor testing, but because of poor samples collected with nasal swabs. According to the article, “False negatives — that is, a test that says you don’t have the virus when you actually do have the virus — may occur. The reported rate of false negatives is as low as 2% and as high as 37%. The false positive rate — that is, how often the test says you have the virus when you actually do not — should be close to zero” (health.harvard.edu). According to research published on The COVID-Tracking Project website (covidtracking.com), since Aug. 30, there have been about 1,000 COVID-19 related deaths per day. In May 2020, there were about 2,500 COVID-19 related deaths per day. As the virus spreads, the number of deaths increase. The US alone has lost 215,000 lives to COVID-19. Konstantinos Damiris, a registered physician at Rutgers University Hospital, was asked if the lower accuracy rates of the rapid tests can lead to another wave of the pandemic; he responded, “Yes, unfortunately another wave is inevitable when relying on test results that are not 100% accurate. However, inaccurate testing is not the only factor in increased cases; it doesn’t help, though.” 

Others believe that even though they may sometimes be inaccurate, rapid tests should still be used. Rapid tests can be issued at schools, at airports, and even at stadiums, enabling quicker identification of infected people before entry. This would exponentially reduce the risk of large-scale transmission in highly populated public settings. For individuals such as teachers, students, nurses, and doctors whose need for rapid and frequent results, the rapid test has the potential to protect families, patients, and even staff members. Denise Tsougas, a registered nurse at Winthrop Hospital, discussed whether she thought it was safe to rely on rapid test results: “Yes, I believe they are safe. I think because this is such a new virus, and we are still working out the kinks with the testing, which is the reason for the lower accuracy.”  COVID-19 tests are becoming more and more accurate as technology evolves.