What’s the difference between Antigen and PCR tests for Coronavirus?

The spread of SARS-CoV-2 and its disease Covid-19 caused a lot of controversies and transformed the shape of modern life in many aspects.

There has never been a time before where the basic knowledge of different types of virus tests was more essential than now. As you now need to understand the difference between the various types of tests available, their reliability, and their accuracy.

When should you get tested?

  • If you have COVID-19 symptoms (i.e. cough, fever, fatigue, or breathing difficulty).
  • If you had close contact with someone who recently tested positive or someone who is suspected of having the virus.
  • If you have participated in activities that put you at increased risk of contracting the virus and didn’t follow the appropriate precautionary measures of social distancing and frequent hand sanitization.

Kindly note that some people who are infected with the coronavirus might be asymptomatic. These individuals don’t show or suffer from any symptoms, but they can still transmit the virus. 

PCR Test

PCR is a molecular test that detects the virus using polymerase chain reaction or PCR. These tests are very accurate when properly performed, but the rapid version could provide false results.

The fluid sample is usually collected by a nasal swab called nasopharyngeal swab inserted into the nostril, or a shorter swab called mid-turbinate swab. In other cases, a long oropharyngeal swab could be inserted into the back of the throat.

PCR results could be available in a few minutes, but may take up to a few days in some cases due to processing delays.

Additionally, the PCR test could detect up to 3 of the same viruses at the same time:

  • Coronavirus (COVID-19)
  • Influenza A and influenza B (Flu)

Yet, it’s important to note that a negative result doesn’t necessarily mean you’re safe.

Antigen Test

The antigen is a diagnostic COVID-19 test that detects certain proteins on the surface of the virus. The positive results are usually accurate, yet there’s a chance of producing false-negative results sometimes.

The fluid sample is usually collected via a long nasal swab, and the results could be produced in a few minutes.

This type of test usually provides results faster than molecular tests. But in some cases, the doctor might recommend a PCR test to verify a negative antigen test result.

Testing Results

  • Positive

A positive result means you are currently infected with the coronavirus. This means you must take all the appropriate steps to treat yourself and avoid spreading the virus. And self-isolation is a must in most cases, after consulting with your certified doctor.

  • Negative

A negative result means that you likely didn’t contract the virus. Yet a false negative result might be common in some cases, based on circumstances surrounding the test sample.

Other Types of Tests

In addition to the previously mentioned common tests, there’s a third type of COVID-19 test that is different in nature and function. It is called the antibody test.

And the antibody test is a serological blood test that uses a finger stick or a blood draw to detect if you have ever been infected by the coronavirus in the past.

But take into consideration that this test doesn’t show if you currently have an active infection, as it only detects antibodies that the immune system develops in response to the virus -not the virus itself.

Ultimately, it takes about a week after being infected for enough antibodies to be developed in your body, in order for the test to detect it in your blood. Yet, scientists are not aware of how long the antibodies stay in the body following an infection.

Finally, we recommend making sure you consult your doctor in every step to avoid putting your health and wellbeing at risk during these testing times.

Please follow all the precautionary measures and stay safe!

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