PCR
Meaning of PCR: PCR rapidly generates millions of copies of a targeted DNA sequence in a test tube, a core technique behind many infection and genetic tests.
Definition of PCR
PCR, short for polymerase chain reaction, is a laboratory technique used to make many copies of a specific segment of DNA from a very small starting sample. The technique relies on repeated cycles of heating and cooling a sample in the presence of an enzyme that copies DNA, along with short sequences that mark the specific segment to be copied.
Each cycle roughly doubles the amount of the targeted DNA sequence present, so that after many cycles a segment present in only a tiny original amount becomes abundant enough to detect and analyze. This makes PCR extremely sensitive compared with older laboratory methods.
PCR is widely used to detect the genetic material of viruses and bacteria in diagnostic testing, to identify inherited genetic changes, and in research settings that require working with a specific DNA sequence, and variations of the basic technique have been developed for specialized diagnostic and research purposes.
Also known as
Used in a sentence
PCR testing confirmed the presence of the virus in the patient's respiratory sample.
Good to know
A positive PCR result indicates that genetic material from an organism was detected, which is not always the same as evidence of an active, contagious infection, since genetic fragments can sometimes be detected after an organism is no longer viable.