Coronavirus Tests: What is the difference between the two tests of Covid, RT-PCR, and antigen? Why do sometimes different results come?


Coronavirus Tests There are many tests to detect Covid-19 but recently the rapid antigen test has become quite popular. This is because you can use it yourself without any medical help. But why do experts still recommend the RT-PCR test?

Coronavirus Tests: In many states of India, once again people are increasingly falling prey to Covid. Recently, Australian all-rounder player Mitchell Marsh was admitted to the hospital for the second test after being found to be Covid positive. This player of IPL team Delhi Capitals was found negative in his first RT-PCR test, while he was found positive in the first test, Rapid Antigen Test. Officials confirmed that some symptoms were observed in the Australian cricketer, after which he was tested.

Like Marsh, this happens to many people who come up positive in an antigen test and then come back negative on RT-PCR, or vice versa. So it is important to know why this happens.

What is the difference between RT-PCR and Rapid Antigen Test?

There can be many ways to get tested for Covid-19. However, RT-PCR and antigen tests are the most popular. RT-PCR is considered to be the most accurate in the Covid test. Samples taken from a person's nose and throat are sent to a lab, where scientists look for RNA or the genetic component of the virus. The presence or absence of genetic material shows whether a person is COVID-19 positive or negative.

However, compared to RT-PCR, the result of the rapid antigen test comes at the same time. This is because an RT-PCR looks at the entire virus RNA, while an antigen test uses a technique that detects only the protein in the virus strain. This is the reason why it can take up to a day for a molecular test to produce a result, while an antigen test gives results in one to 30 minutes.

Why RT-PCR test report is wrong despite symptoms of Covid

There can be many reasons behind this, which determine the accuracy of the tests. Also why RT-PCR test returns negative despite classic COVID symptoms like fever, sore throat, fatigue, body aches, and cough.

While many experts blame the test's inability to detect new coronavirus variants, others believe it could be due to the low viral load in the body. Symptoms of COVID-19 can usually be seen within two to 14 days after infection. The virus begins to appear on the fifth day of the infection cycle. So if you get the test done before that, the chances of getting the result wrong increases. Also, the test can come up as a false positive or negative if the swab stick is not used to take samples of the nose and throat in the right way.

Common symptoms of covid

If you feel these symptoms of Covid-19 infection, then isolate yourself without waiting for the test results.

  • Fever
  • Persistent cough
  • Sore throat
  • Weakness
  • Muscle and joint pain
  • Loss of taste and aroma
  • Running nose
  • Sneeze
  • Gastrointestinal problems

Other tests to detect Covid-19

You can get an antibody test or serology test done to detect Covid-19 infection. However, this is a kind of blood test, which shows whether you have had Covid-19 before or not. The antibody test does not detect active coronavirus infection but detects the presence of the viral particle several days after infection. Therefore, it is okay to do this test only after 14 days of showing symptoms.

Covid antigen self-test has become quite popular these days. You will not need medical help for this test. It is like a rapid antigen test that gives results in no time. However, there are many times wrong results in this too, so experts recommend doing an RT PCR test only.

Disclaimer: The advice and suggestions mentioned in the article are for general information purposes only and should not be taken as professional medical advice. Always consult your doctor if you have any questions or concerns.