Polymerase chain reaction (PCR) is a method of detecting specific sequences of DNA or RNA (types of genetic material) even when only a tiny amount is available. That's because PCR targets sections of the DNA or RNA, and then reproduces and amplifies them. The process is performed in a test tube and takes only a few hours.
It's common to come across this term in chronic fatigue syndrome research that involves testing for pathogens, such as viruses or bacteria. When used in this way, PCR allows scientists to identify the source of the genetic material and therefore identify which pathogens are present.
Other uses of PCR include:
- Diagnosing genetic disease or certain malignant cancers
- Establishing biological relationships (as in paternity tests)
- DNA forensics in criminal investigations
Polymerase is an enzyme that helps replicate or repair DNA, and in the lab it can be used to very quickly make millions of copies.
You may also come across the term reverse transcript PCR, or RT-PCR. This is a highly sensitive method for detecting and analyzing messenger RNA. RT-PCR can be used to measure viral load in patients with HIV and is also useful for work involving RNA viruses, such as mumps and measles.