How PCR Tests Work
PCR testing has three steps: Material collection, extraction, and PCR. Let’s examine them one by one.
- The collection stage consists of inserting a swab into the patient’s nose and/or pharynx, to collect material from their respiratory canal. After extraction, the sample will be sent for analysis.
- Extraction will be performed by laboratory technologists, who will extract the genetic material from the sample. This genetic material may or not include the virus’s genes.
- The sample will then undergo a Polymerase Chain Reaction (PCR). Basically, the technologists will use a PCR machine to “amplify” the DNA sample. This stage will also involve the use of chemicals. One of these chemicals will produce a fluorescent light if it detects the presence of the virus’s genetic material.
Results for PCR tend to be available within 72 hours.
A virus survives by producing copies of itself within the body of a host, be it a human or an animal. Therefore, a virus’s genetic material will be present in the host’s body.
Some viruses produce DNA, while others, such as SARS-CoV-2, produce RNA. PCR tests are designed to detect the SARS-CoV-2 RNA in the body of the host. Namely, in their respiratory canal.
Polymerase chain reaction (PCR) is the process of amplifying – or making many copies – of a short piece of RNA or DNA. PCR is used to detect a known sequence of RNA/DNA. Using very specific probes designed to bind the DNA sequence of interest, a short piece of DNA is amplified through many cycles of heating and cooling. PCR amplification allows scientists to determine if a piece of DNA is present in a sample.