What is Polymerase Chain Reaction (PCR)?

Polymerase Chain Reaction (PCR) is a molecular biology technique that seeks to amplify a fragment of genetic material millions of times. The PCR technique has innumerable applications and is becoming more and more widely used.

In addition, the polymerase chain reaction (PCR) allows a few DNA fragments to replicate into millions or billions of copies. DNA amplification allows us to study the DNA molecule in detail in the laboratory.

What is PCR?

It consists of highly specific replication of a fragment of genetic material millions of times. Diagnosis by PCR has a certain complexity. It requires trained personnel for its correct performance and interpretation.

This technique is used to detect any microorganism present in samples from patients who have been infected.


It is fairly simple to understand and use, and produces results quickly.
The technique is very sensitive and has the potential to produce millions to billions of copies of a specific product for sequencing, cloning and analysis.
This test is a very powerful and practical research tool.
Minimally invasive: performed with nasal swabs, throat swabs, and testing of saliva or other body fluids.
Allows social distancing: while some molecular tests, including RT-PCR, are usually performed in a hospital or clinic, swabbing can also be arranged from the patient’s car or at home.
Fewer false negatives in some cases: deep nasal swabs will have fewer false negatives compared to other tests, such as throat swabs or saliva tests.

PCR applications

  • Selective DNA isolation
  • DNA amplification and quantification
  • Medical and diagnostic applications
  • Infectious disease applications
  • Forensic applications
  • Research applications

How are they used?

This tests are used to:

  • Diagnose certain infectious diseases
  • Identify a genetic change that may cause a disease
  • Find small numbers of cancer cells that might be missed by other types of tests.

How are they done?

  • Taking a sample of blood, saliva, mucus or tissue.
  • The sample has your own DNA and possibly the DNA of a pathogen or cancer cell.
  • The sample is put into a special machine. An enzyme called polymerase is added to the sample. This causes the sample to make copies.
  • The copying process is repeated several times. After an hour, billions of copies are made. If there is a virus or pathogen, this is indicated on the machine.

You can read much more and in depth in our blog