What is
PCR?

PCR is one of the most important scientific advances of the 20th century

Polymerase chain reaction (PCR) is an efficient and cost-effective way to copy small specific DNA or RNA sequences.

Plants and animals, bacteria and viruses—every organism has its own unique nucleic acid sequences. Using PCR, millions of copies of fragments within these sequences can be made in a short amount of time. It is an innovative yet simple method that serves as an invaluable tool in the field of molecular diagnostics.

Even with minimal amounts of sample, PCR enables reliable diagnosis and monitoring of diseases, providing high sensitivity that may not be possible with other diagnostic methods, like culture or serology. The accuracy, precision, and reliability of PCR are among the reasons it is considered the “gold standard” by many in the diagnostic community.

Real-world applications of the “DNA photocopier”2-6

From diagnostics, research, and prenatal care to agriculture and forensics, PCR techniques are an essential element in the arsenal of today’s scientists.

PCR is most commonly used in diagnosing infections like influenza, COVID-19, Human Immunodeficiency Virus (HIV), Chlamydia trachomatis, and viral hepatitis among others. It has also helped to revolutionize cervical cancer screening, and plays a critical role in ensuring the blood supply stays safe.

Beyond an initial diagnosis, PCR is also used to make personalized healthcare possible.

  • For instance, measuring a person’s viral load (the amount of virus present in a person’s body) allows healthcare professionals to gauge how well a medicine or treatment is working. This is an essential part of managing certain chronic infections, such as HIV or hepatitis B
  • PCR can also play a role in liquid biopsy testing (a simple and non-invasive alternative to surgical biopsies) to identify the presence of specific gene mutations (e.g. EGFR and KRAS) in cancers (e.g. lung and colorectal cancer).

The high sensitivity and broad-spectrum application of PCR make it a leading choice in molecular laboratories. However, there are other important complementary technologies, like next-generation sequencing, that have the potential to unlock new information about the role of nucleic acids in disease.