If you are someone who is experiencing symptoms of COVID-19, or have been exposed to someone who has symptoms or recently tested positive, you should take the next step to get tested.
But before you do, it is important to know the differences between polymerase chain reaction (PCR) tests and rapid antigen tests. Having this knowledge in your back pocket could not only protect yourself, but also those you care for. When you know what sets these tests apart, you will feel more empowered to handle the virus, as well as know which next steps to take to keep yourself and those around you safe.
What’s the difference between a PCR and antigen test for COVID-19?
PCR and antigen tests are available to detect if you have Covid. The tests are often confused with one another, but they have some major differences.
The PCR test detects the presence of the virus’s genetic material or its fragments as the material breaks down - even before the presence of symptoms. Because of this, PCR testing for Covid is widely considered the most reliable or “gold standard” option for identifying an active infection. The medical community has been able to flatten the curve and lessen the spread of the virus throughout the pandemic largely due to PCR test accuracy.
Antigen tests, on the other hand, only detect proteins on the surface of the virus called antigens. Antigen tests typically take only 15 to 30 minutes to produce results, which is why they are also referred to as “rapid tests.”
Rapid antigen tests are recommended only when you use them within a few days of the start of symptoms, as this is when the largest amount of virus is present in your body.
Which Covid test is more accurate?
While the antigen test is faster to produce results, it is less sensitive than the PCR test. So, rather than relying solely on Covid rapid test accuracy, especially if you’re using a home test, you should also get your results confirmed by a lab professional via a PCR test. A PCR test is considered the most reliable test available, with higher accuracy when compared to the antigen test. In fact, according to the FDA, “early data suggests that antigen tests detect the Omicron variant, but they may have reduced sensitivity.”
Because PCR test accuracy is often higher than antigen tests, your healthcare provider may request a PCR test to confirm a negative antigen test result.
What exactly is the PCR test accuracy rate?
Antigen tests are often considered a first step in the testing process for many who are seeking quick results, however, the sensitivity of the test can vary based on the course of the infection. While PCR testing sensitivity can also vary, it is still the gold standard, because of its superior accuracy. If you want to maximize your chances of getting the most accurate Covid test result, then you should get a PCR test between five to seven days after exposure to a person with Covid. This window is recommended as it is when the virus has had ample time to replicate.
Why is that? PCR tests identify genetic material from the virus, and an infected person can produce a negative result if they do not have enough genetic material for the test to detect. This can happen even in a lab analysis. As a result, you should always strive to test within the five to seven day window to maximize your chances for Covid PCR test accuracy. Many people wonder why the PCR is so accurate. The amplifying property of PCR allows the test to successfully detect even the smallest amount of coronavirus genetic material in your sample. As a result, the PCR test is highly sensitive, with its accuracy approaching 100%.
Bottom line: the PCR test is the best testing tool the medical community has to diagnose SARS–CoV–2, or COVID-19.
Are there any limitations with PCR tests?
While PCR tests are highly accurate, they do have some drawbacks. The test requires a skilled laboratory technician with special equipment to run them properly and obtain the result. Secondly, the amplification process can take an hour or more from start to finish.
Typically, only large, centralized testing facilities – such as hospital labs – have the capacity to run multiple PCR tests simultaneously. Between sample collection, transportation, amplification, detection, and reporting, some test results are reported within 24-hours after sample collection. However, sometimes it can take a few days, depending on how long it takes the sample to reach the laboratory.
What about PCR tests and false positives?
One of the biggest advantages of PCR testing is that the likelihood of receiving a false negative or a false positive is very low. PCR test accuracy is measured by the number of positive cases detected. A study in January of 2021 found mucus PCR tests diagnosed COVID-19 correctly in 97.2% of cases. In addition, while the medical community is still determining the exact accuracy of the tests, recent trials have shown the tests to be up to 99% accurate.
If accuracy matters - and it does - choose PCR Covid testing
While rapid antigen tests remain a vital part of containing and managing Covid-19, you should think of them as just the first step in getting tested for the disease. PCR tests, such as those provided by IHD Labs, are much more sensitive and suited for Covid testing accuracy. This makes the PCR a better tool in diagnosing Covid accurately, reliably, and managing it successfully in the future.
Along with vaccines, masking, contact tracing, and social distancing, PCR testing is one of the best tools in our possession to lessen and eventually defeat Covid-19.