The nose swab PCR test for COVID-19 is an accurate and reliable test for diagnosing COVID-19. A positive test means you likely have COVID-19. A negative test means you probably did not have COVID-19 at the time of the test. Get tested if you have symptoms of COVID-19 or have been exposed to someone who tested positive for COVID-19.
PCR means polymerase chain reaction. It’s a test to detect genetic material from a specific organism, such as a virus. The test detects the presence of a virus if you have the virus at the time of the test. The test could also detect fragments of the virus even after you are no longer infected.
Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy
The polymerase chain reaction (PCR) test for COVID-19 is a molecular test that analyzes your upper respiratory specimen, looking for genetic material (ribonucleic acid or RNA) of SARS-CoV-2, the virus that causes COVID-19. Scientists use the PCR technology to amplify small amounts of RNA from specimens into deoxyribonucleic acid (DNA), which is replicated until SARS-CoV-2 is detectable if present. The PCR test has been the gold standard test for diagnosing COVID-19 since authorized for use in February 2020. It’s accurate and reliable.
Your healthcare provider may recommend testing for COVID-19 if you have any of the following symptoms:
Not everyone with COVID-19 develops symptoms. And not all symptomatic people develop all of the symptoms listed above. Please check with your healthcare provider if you’re feeling unwell during the COVID-19 pandemic — even if you’ve been vaccinated.
There are three key steps to the COVID-19 PCR test:
A positive test result means that it's likely that you have an infection with SARS-CoV-2. This could be due to asymptomatic infection, but if you have symptoms, then this infection is called COVID-19. Most people have mild illness and can recover safely at home without medical care. Contact your healthcare provider if your symptoms get worse or if you have questions or concerns.
A negative test result means you probably didn't have an infection with SARS-CoV-2 at the time your specimen was collected. However, it's possible to have COVID-19 but not have the virus detected by the test. For example, this may happen if you recently became infected but you don’t have symptoms yet — or it could happen if you've had COVID-19 for more than a week before being tested. A negative test doesn’t mean you are safe for any length of time: You can be exposed to COVID-19 after your test, get infected and spread the SARS-Cov-2 virus to others.
If your test is positive, talk with your healthcare provider, stay home and separate yourself from others. If your test is negative, continue to take steps to protect yourself and others from getting COVID-19. Read more about what to do if you test positive and ways to prevent getting infected with COVID-19.
You should receive your test results as early as 24 hours after sample collection, but sometimes it can take a few days, depending on how long it takes the sample to reach the laboratory.
Because the PCR test is so sensitive, it can detect very small amounts of virus material. This means that the test can continue to detect fragments of SARS-CoV-2 virus even after you’ve recovered from COVID-19 and are no longer contagious. So you may continue to test positive if you've had COVID-19 in the distant past, even though you can’t spread the SARS-CoV-2 virus to others.
Prolonged infection in immunocompromised individuals can occur where they shed infectious virus for months. Also, healthy people can become reinfected. If you test positive for SARS-CoV-2 but you think you might have already recovered from COVID-19, please discuss with a healthcare provider.
There are two types of tests for COVID-19: the PCR test and the antigen test.
The antigen test is typically faster but is less sensitive than the PCR test. Because the antigen test is not as accurate as PCR, if an antigen test is negative, your healthcare provider could request a PCR test to confirm the negative antigen test result.
If you have symptoms of COVID-19 or were exposed to people who have symptoms or have tested positive, you may want a test. First, talk with your healthcare provider. They will review your symptoms in person or on a video appointment. If needed, the provider orders a test and helps you find a testing location and time. Keep in mind that if you’ve been exposed to the SARS-CoV-2 virus but don’t have symptoms, call the testing site first to make sure they can accommodate you.
You can also call or check the websites of your local hospitals in your health insurance network or check with community health centers or urgent care centers. The U.S. Department of Health and Human Services provides links to find community-based testing sites in your state. You can also check your state or local health department websites for the latest information on testing locations. The Centers for Disease Control provides links to these state and local health departments.
A note from Cleveland Clinic
Accurate and quick tests are key to slowing the spread of COVID-19. If you develop symptoms, please call your healthcare provider or your local public health department to determine where to go for testing. Trust your healthcare provider to recommend the quickest, most accurate test available. To keep those around you safe, you should wear a face mask that fits snugly over your nose, mouth and chin, and avoid close contact with others until you get the results of your COVID test. Be sure to monitor your symptoms and seek emergency care if you have:
Last reviewed by a Cleveland Clinic medical professional on 08/24/2021.
Learn more about our editorial process.