PCR (polymerase chain reaction) tests are a fast, highly accurate way to diagnose certain infectious diseases and genetic changes. The tests work by finding the DNA or RNA of a pathogen (disease-causing organism) or abnormal cells in a sample.
DNA is the genetic material that contains instructions and information for all living things. RNA is another type of genetic material. It contains information that has been copied from DNA and is involved in making proteins.
Most viruses and other pathogens contain DNA or RNA.
Unlike many other tests, PCR tests can find evidence of disease in the earliest stages of infection. Other tests may miss early signs of disease because there aren’t enough viruses, bacteria, or other pathogens in the sample, or your body hasn’t had enough time to develop an antibody response.
Antibodies are proteins made by your immune system to attack foreign substances, such as viruses and bacteria. PCR tests can detect disease when there is only a very small amount of pathogens in your body.