PCR Tests

PCR (polymerase chain reaction) tests are a reliable and accurate way to diagnose certain infectious diseases, some types of cancer, and certain genetic changes. The tests check for small amounts of genetic material of a pathogen (disease-causing organism) or abnormal cells in a sample of your blood, saliva, mucus, or tissue. The genetic material could be: DNA, which contains the genetic information needed for a person and most other living things to develop and grow.

DNA is copied from one generation to the next.; RNA, which contains information copied from DNA. Many types of RNA help your cells make proteins. Some viruses use RNA instead of DNA to carry their genetic information.; Most viruses and other pathogens contain DNA or RNA.

Unlike many other tests, PCR tests can find signs of disease in the earliest stages of infection. They can also find pieces of a virus you had, after you are no longer infected. Other tests may miss early signs of disease because there aren't enough viruses, bacteria, or other pathogens in your sample, or your body hasn't had enough time to develop an antibody response.

Antibodies are proteins your immune system makes 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. As part of a PCR test, a small amount of genetic material in your sample is copied multiple times.

The copying process is known as amplification. If your sample contains pathogens, amplification can make them much easier to detect.

How to prepare

You don't need any special preparations for a PCR test.

Sample type

Blood Swab

Other names for this test

polymerase chain reaction, rtPCR, reverse transcription PCR, qPCR, quantitative PCR, real-time PCR