What is a PCR test?

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.

What is a COVID-19 PCR test?

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.

Who should get tested for COVID-19?

Your healthcare provider may recommend testing for COVID-19 if you have any of the following symptoms:

  • 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.

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.

TEST DETAILS

There are three key steps to the COVID-19 PCR test:

  1. Sample collection: A healthcare provider uses a swab to collect respiratory material found in your nose. A swab is a soft tip on a long, flexible stick that goes into your nose. There are different types of nose swabs, including nasal swabs that collect a sample immediately inside your nostrils and nasopharyngeal swabs that go further into the nasal cavity for collection. Either type of swab is sufficient for collecting material for the COVID-19 PCR test. After collection, the swab is sealed in a tube and then sent to a laboratory.
  2. Extraction: When a laboratory scientist receives the sample, they isolate (extract) genetic material from the rest of the material in the sample.
  3. PCR: The PCR step then uses special chemicals and enzymes and a PCR machine called a thermal cycler. Each heating and cooling cycle increases (amplifies) the amount of the targeted genetic material in the test tube. After many cycles, millions of copies of a small portion of the SARS-CoV-2 virus’s genetic material are present in the test tube. One of the chemicals in the tube produces a fluorescent light if SARS-CoV-2 is present in the sample. Once amplified enough, the PCR machine can detect this signal. Scientists use special software to interpret the signal as a positive test result.