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What is PCR?

PCR is one of the most important scientific advances of the 20th century1

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.

PCR is about finding the smallest necessary fragment of the nucleic acid code of life…and amplifying the number of copies of that target, to the point where it's very easy to detect or quantify.

Dmitriy Kosarikov
Senior Director, Development Lead - 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.

Female-lab-technicians-loading-test-tubes

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.

Male-healthcare-professional-consulting-a-female-patient

Watch our Director of Assay Development, Dmitriy Kosarikov, talk about the role of PCR in diagnostics.

What is PCR

The history of PCR

1983 date graphic

In 1983, Kary Mullis, PhD, a scientist at the Cetus Corporation, conceived of PCR as a method to copy DNA and synthesize large amounts of a specific target DNA.

1991 date graphic

In 1991, Roche saw the potential in PCR and invested in refining the science for use in molecular diagnostics to detect pathogens and genetic code changes that lead to diseases. Roche has not only refined PCR, but it has remained the clear leader and innovator of this technology.

In the years to follow, Roche transformed PCR into an ecosystem of standardized, high-value-added and widely available diagnostic tools, including innovative platforms, advanced assay designs, and robust robotics, software, and information systems.

Molecular innovation without limits 

 

This extensive expertise and robust infrastructure are unique and essential components of Roche’s ability to innovate and be a leader in molecular diagnostics.

Today, Roche combines its industry-leading systems, comprehensive assay menu, physical and virtual automation solutions, and unparalleled consulting capabilities into a first-of-its-kind Molecular Work Area. With it, laboratories of all sizes and disciplines can unlock the true potential of PCR and bring confident, timely results to patients everywhere.

References

  1. Keros T, Borovecki F, Jemersić L, Konjević D, Roić B, Balatinec J. The centenary progress of molecular genetics. A 100th anniversary of T. H. Morgan's discoveries. Coll Antropol. 2010;34(3):1167-1174.
  2. Mullis KB, Faloona FA. Specific synthesis of DNA in vitro via a polymerase-catalyzed chain reaction. Methods Enzymol. 1987;155:335-350.
  3. Salki RK, Bugawan TL, Horn GT, et al. Analysis of enzymatically amplified beta-globin and HLA-DQ alpha DNA with allele-specific oligonucleotide probes. Nature. 1986;324(6093):163-166.
  4. Salki RK, Gelfand DH, Stiffel S, et al. Primer-directed enzymatic amplification of DNA with a thermostable DNA polymerase. Science. 1988;239(4839):5.
  5. Mullis, KB. The unusual origin of the polymerase chain reaction. Sci AM. 1990;262(4):56-61, 64-55.
  6. Mullis, KB. Target amplification for DNA analysis by the polymerase chain reaction. Ann Biol Clin (Paris).1990;48(8):579-582.