What Methods Are Used For COVID-19 Testing?

COVID-19 spreads rapidly. One of the key ways to slow the pandemic is through accurate testing. Because COVID-19 is a new virus, accurate testing is a challenge, but much improvement has been made since the first cases were reported.

Modern medical technology has allowed us to discover better ways to detect COVID-19 and properly quarantine the infected. While no tests used for COVID-19 testing are 100% accurate, here are the three most common tests used today that give us the most accurate results thus far:

1. Stand-Alone PCR Test

The polymerase chain reaction(PCR) test was invented in 1984 by Kary Mullis, a biochemist. While the test does not specifically detect COVID-19, it detects genetic evidence of viral material through nasal or oral mucus samples. Because this test detects any genetic material from any virus, it is recommended to take this test within five days of exposure for the most accurate results.

The CDC has designated the PCR test to be the primary method for COVID-19 testing in the USA. It is estimated that only 30% of PCR tests are inaccurate, putting it on par with similar tests that detect the flu. However, the majority of that 30% are false-negative results, so if you happen to test positive, you probably are infected.

2. Saliva PCR Test

The saliva PCR test is an adaptation of the standard PCR test that utilizes saliva instead of mucus to identify viral genetic material. Its accuracy is just below the accuracy of a standard PCR test from what has been observed so far, but more application of this method is needed to form a more solid conclusion.

Because this testing procedure does not depend on chemical additives to determine the outcome, the saliva test is not as accurate as the standard PCR test. However, perfecting this test could lift a heavy burden on medical supplies as not as much equipment is needed.

The main advantage of this test is that saliva is much easier to collect than mucus samples, which require a long nasal swab inserted deep into the nose or throat.

3. Antigen Test

Antigen tests used for COVID-19 testing can produce much faster results, but accuracy is sacrificed due to the need for rapid results.

Instead of looking for genetic material, an antigen test looks for proteins that are commonly found on the surface of a virus. Sometimes the test will pick up similar proteins that are related to but not necessarily COVID-19, triggering a false-positive.

While false-positives are rare, about 50% of all inaccuracies are false-negatives. It is not uncommon for a doctor to recommend a PCR test after a negative antigen test because of the high rate of false-negatives.

As you can see, testing for COVID-19 is not an exact science, but it is improving every day. It is always best to follow COVID-19 guidelines that state if you feel you have been exposed, quarantine yourself until any symptoms subside. For more information about COVID-19 testing, contact a local physician. 


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