Covid-19 Rapid Antigen Testing or PCR Test?

rapid antigen testing

Rapid antigen tests are often also referred to as a viral or rapid tests. An antigen test detects a protein coating the surface of the SARS-CoV-2 virus. The PCR (Polymerase Chain Reaction) test is considered a molecular test. The collected sample is converted into DNA, where it can be positively identified if present in the sample. Which one should you select?

As Covid-19 continues its course with new variants, our knowledge of the virus must evolve with it. This includes not only understanding vaccines, but also understanding the types of testing available to us. While all testing is critical to preventing the spread of Covid-19, it is best to recognize which testing method may be preferable for you and your loved ones.

PCR test

The PCR (Polymerase Chain Reaction) test is considered a molecular test. They are also referred to as diagnostic tests. They are taken via nasal swabs. Some are done as a saliva test; however, this is less common. The collected sample is then converted into DNA, where it can be positively identified if present in the sample.

Standard PCR tests must be sent to a lab for processing and may take 1 – 3 business days to return results. Rapid PCR tests can be processed onsite and typically produce results within hours.

Antigen test

Rapid antigen tests are often also referred to as a viral or rapid tests. An antigen test detects a protein coating the surface of the SARS-CoV-2 virus. Typically, these are collected through nasal swabs and then placed into a solution to identify the virus. These types of tests can produce results in as little as fifteen minutes. Because antigens tests are affordable and do not need to be sent to a lab, they are ideal for large groups and events, as they allow many individuals to get tested in a short time frame.

What is the difference?

Both tests detect an active case of Covid-19. The main difference between the PCR vs. antigen test, lies in the timeframe and accuracy.

While the antigen tests are often much quicker, they are not as accurate as a PCR test, especially in the early stages of Covid-19. This test has a higher rate of producing false negatives. This is because they may have a lower sensitivity, which means they may miss some infections and may require multiple tests to ensure the virus is not present.

When looking at testing time frames, the PCR tests usually take longer. This is because results usually must be sent to a lab. The results can be received from 1-3 days. PCR tests are highly accurate and do not often need to be repeated. More recently, rapid PCR tests have become available. These results are typically received the same day.

More About Rapid Antigen Test (At-Home COVID-19 Test)

The at-home COVID-19 test kits, also known as Rapid Antigen Tests, are a tool to provide surveillance for infections. They also help us to try to prevent outbreaks of infections. They are especially useful because they provide quick results. When done properly, rapid antigen tests provide you with results quickly – especially helpful for work or school.

Self-testing is an important tool in our effort to stop the spread of COVID-19, along with vaccination, masking, washing hands and social distancing. To get the most accurate result, it is important that you read the label carefully, follow the directions and do the test properly.

COVID-19 Rapid Antigen Testing FAQs

A Rapid Antigen Test is a faster way to detect if you have a current COVID-19 infection. It can be done completely at home using a swab that is exposed to a solution that detects the presence of a protein part of the virus called an antigen. Results are typically ready in just 15 to 30 minutes.

Rapid antigen testing may be helpful if you do not have symptoms of COVID-19 and would like quick results to meet a testing requirement for an event or travel.

Regardless of your test result, you should discuss your results with your doctor and continue to follow any safety precautions recommended by public health experts. This can help you and your community better manage the risks and benefits of resuming daily activities.

A sample is collected through a nasal or throat swab and mixed with a solution. The solution is then placed onto an indicator device that may detect the presence of the virus that causes COVID-19.
The accuracy level of Rapid Antigen Tests is good. However, Rapid antigen tests are less accurate than molecular (PCR) tests, so your doctor may recommend a PCR test when your antigen test result does not make sense with your symptoms and exposure history. For example, when the antigen test says you are infected, but you do not have symptoms (and have not been exposed recently). Another example is when your antigen test says you are not infected but you have symptoms. Rapid antigen tests have their best accuracy within 7 days of symptoms starting. Accuracy and the clinical significance of results beyond 7 days is not known.
At-home testing kits for COVID-19 are currently available and safe to use. However, not all kits should be considered for their ability to provide accurate results. Pay attention to the label. The testing kit should include testing for E protein and N protein.

Antigen tests look for specific proteins on the surface of the virus. The at-home testing kit may target only on one antigen or more than one antigen. For example, for Omicron the S protein is mutated. If the at-home testing kit targets the S protein only, the At-Home Test Kit may be inaccurate.

It is recommended that if you have symptoms of COVID-19, an at-home test is one way to get quick and reliable results. Once symptoms have appeared, the amount of virus in your body (viral load) is high, which means the antigens are more likely to be picked up by a test.

COVID-19 symptoms usually appear two to 14 days into infection. You might consider an at-home test kit for COVID-19 if you have:

  • Fever or chills
  • Cough
  • Shortness of breath or difficulty breathing
  • Fatigue
  • Muscle or body aches
  • Headache
  • New loss of taste or smell
  • Sore throat
  • Congestion or runny nose
  • Nausea or vomiting
  • Diarrhea

If the results of your COVID-19 test were negative and you had symptoms at the time of the test, chances are the result is accurate and your symptoms were caused by another infection or virus. However, if your symptoms continue, you may want to do another test to confirm your result. You should also continue to isolate while you are sick. You can contact us at Everest Urgent Care to determine if you should see a physician for treatment.

If the results were negative and you have no symptoms, your result is likely negative. However, if your exposure to COVID-19 was recent, you may want to repeat the test.

If you were exposed to someone with COVID-19, you are not vaccinated, you are asymptomatic, and your test result was negative, you should quarantine for 14 days. Your may have tested too early to provide accurate results.

If you are not confident that your results were accurate and you used an at-home rapid antigen test, you may want to take a PCR test to confirm or check the results.

If you have any questions or concerns, contact us immediately for information or additional testing.

If your COVID-19 test is positive, isolate yourself to avoid spreading the virus to others.

You should notify your close contacts of your positive test result.

Call your doctor to discuss your diagnosis and / or treatment options.

The Everest Urgent Care medical experts, with two locations in Upper Darby and Chester, PA, are available to help you with symptom management and treatment options.

Call Everest Urgent Care

Upper Darby (610) 352-8000 | Chester (484) 480-4700