Two types of COVID-19 tests, the rapid antigen test and the polymerase chain reaction (PCR) test, are available in the United States. The PCR typically relies on lab testing and is still considered the "gold standard" for accuracy.
The rapid tests are commonly at-home tests, with new options that have made testing easier. Not every test is created equal, though, and there are pros and cons to each type of COVID-19 test. helicobacter pylori stool test
As of November 2023, each U.S. household was again eligible for four free at-home rapid antigen tests ordered online.
This article discusses the types of COVID tests and how they are used. It offers information to help you choose an at-home test, as well as how to determine when a healthcare provider or lab may be needed to ensure access to some tests and results.
The Food and Drug Administration warns people to avoid counterfeit over-the-counter (OTC) COVID-19 diagnostic tests that are not authorized by the FDA. Signs that a test may be counterfeit include the following:
Polymerase chain reaction (PCR) tests are considered the "gold standard" for COVID-19 tests. PCR tests are a type of nucleic acid amplification test (NAAT) that takes a small sample of genetic material and copies it multiple times. This process is called amplification.
Amplifying the genetic material makes detecting even the smallest amount of a virus easy. PCR tests can also differentiate between different virus variants—or strains. Since these tests examine microscopic bits of a virus's genetic material, they are highly reliable—often close to 100%.
The drawback of the PCR process is the time it takes and the fact that lab analysis is required to get results. The average turnaround time for PCR test results is two to three days after the lab receives your sample.
There are also a few options for NAATs that can be used at outpatient clinics and can provide a result in about 20 minutes. These tests look for nucleic acid from the virus instead of antigen.
Can detect virus in asymptomatic people
Sample must be sent to a lab
Lengthy turnaround time (3-7 days)
Rapid antigen tests look for pieces of the viral proteins from the SARS-CoV-2 virus (antigens) that cause COVID-19 rather than genetic material (nucleic acid from the virus). These tests are quick and are often used to detect other viruses that cause illnesses like the flu, respiratory syncytial virus (RSV), and sexually transmitted infections (STIs).
The FDA has approved several rapid antigen tests for COVID-19 because they offer a more simple and accessible option for testing. They can also produce results within minutes.
These are general instructions on COVID rapid test use. Each test is different, so it's important to follow the instructions provided with the self-test you're taking.
Antigen tests are not as sensitive as PCR-based or other nucleic acid amplification tests. PCR tests can detect the COVID-19 virus nearly 100% of the time. Antigen tests can only detect the virus in about 80% of people with COVID-19 symptoms. The accuracy is much lower in people who take the test when they have no symptoms.
Cheaper than a PCR test
User error can effect results
Doesn't work well if you don't have symptoms
There is no right or wrong answer when it comes to which COVID-19 test is best. There is a time and place for each type, and which one you choose will depend on your situation and symptoms.
For example, if you are sick and wondering whether your symptoms could be caused by COVID-19, a rapid test can give you that answer quickly. That's helpful because it would allow you to isolate yourself from other people to help reduce the spread of the virus.
Both PCR and antigen testing use samples of cells collected from your nose, mouth, or throat. PCR sample collections can be done at home but have to be sent to a lab for results. Rapid antigen tests can be done completely at home.
However, if you do not have symptoms or you're simply taking a test before an event to make sure that you're not sick, a rapid antigen test may not be able to give you the most accurate result.
People who are symptomatic who need testing before a medical procedure, people who are testing because they were exposed to someone with COVID-19, or people who remain sick despite numerous negative rapid tests are the best candidates for PCR testing. While this type of testing takes longer and is more expensive than rapid tests, it can provide you with the most accurate result.
PCR tests are generally considered more accurate than rapid tests, but rapid tests have benefits that PCR tests do not have—for example, they provide results faster and for a lower cost. The test that is right for you will depend on why you are taking the test and how soon you need to get results.
When you should test will depend on whether or not you are experiencing COVID-19 symptoms.
If you have COVID symptoms: Take a PCR test if you plan to use only one test. An antigen test is reliable for a positive result, but a negative result is more accurate with a PCR. If your rapid antigen test is negative, take another test in 48 hours or use a PCR test as soon as you can.
If you don't have COVID symptoms: Wait at least five days from when you were exposed before taking either a PCR or antigen test. The same limitations and next-test recommendations apply (i.e., a negative antigen test is less reliable). If a second antigen test is negative after 48 hours, wait another 48 hours and test again.
For people testing after a COVID infection, the CDC recommends antigen tests. You do not need to take a test if you have no symptoms and it's still within 30 days of your last positive test.
People often take a COVID test before traveling, or attending family gatherings and public events. The recommendation from the Centers for Disease Control and Prevention is to do these tests as close to the event time as possible, within one or two days.
There are several ways to access a COVID-19 test. They include:
Check with your healthcare provider about COVID tests, too. They may offer testing, including antigen and PCR tests. If you have insurance, check your coverage to see what types of tests are covered since the May 2023 end of the COVID public health emergency.
Keep in mind that you can collect samples for both PCR and rapid antigen tests at home, but you can only get immediate results with a rapid antigen test. It's possible (but unlikely) to get PCR test results in a few hours if you have direct access to a lab and there is no one else waiting.
The COVID-19 test that you choose will depend on how you are feeling, why you are taking a test, and how vulnerable the people around you are to getting sick. If you need immediate results, a rapid antigen test might be the best option. However, if you need the most accurate test, or you are still sick and want to validate your rapid test result, PCR is the better choice.
If you have questions about COVID-19 testing, symptoms, or treatment, talk to your doctor or another trusted healthcare provider.
The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.
Centers for Disease Control and Prevention. COVID-19 Testing: What You Need to Know.
United States Postal Service. Place Your Order for Free At-Home COVID-19 Tests.
Food and Drug Administration. Counterfeit At-Home OTC COVID-19 Diagnostic Tests.
Crozier A, Rajan S, Buchan I, et al. Put to the test: use of rapid testing technologies for COVID-19. BMJ. February 2021;372:n208 doi:10.1136/bmj.n208
Hafer N. What’s the difference between a PCR and antigen COVID-19 test?.
Abbott. COVID-19 Rapid Testing: Every Minute Counts.
Centers for Disease Control and Prevention. Considerations for SARS-CoV-2 Antigen Testing for Healthcare Providers Testing Individuals in the Community.
Infectious Disease Society of America. IDSA Guidelines on the Diagnosis of COVID-19: Antigen Testing.
Department of Health and Human Services. Community-Based Testing Sites for COVID-19.
By Rachael Zimlich, BSN, RN Rachael is a freelance healthcare writer and critical care nurse based near Cleveland, Ohio.
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