Molecular Diagnostics:

Polymerase Chain Reaction (PCR) is a widely used technique in Molecular Diagnostics.
A DNA polymerase is used to amplify (replicate) a fragment of DNA. As the reaction continues, this fragment of DNA is used as a template for replication, thus starting a chain reaction of amplification that is capable of generating millions of copies of the original DNA fragment.

The applications of PCR in clinical medicine are many, and its use in the Hematopathology area has proven to be very beneficial in aiding in the diagnosis and follow up of many hematological malignancies such as Leukemia and Lymphoma.