3 Key Steps to the COVID-19 PCR Test

The PCR test has been the gold standard test for diagnosing COVID-19, it’s accurate and reliable. There are three key steps to the COVID-19 PCR test:

• 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.
• Extraction: When a laboratory scientist receives the sample, they isolate (extract) genetic material from the rest of the material in the sample.
• 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.