Polymerase Chain Reaction (PCR)


Polymerase Chain Reaction (PCR)

What is Polymerase Chain Reaction (PCR)?

The Polymerase Chain Reaction (PCR) is a molecular biology technique that enables cytogenetic technologists to detect and analyze specific gene sequences in a patient’s sample. The PCR method allows for the amplification of small sections of DNA. For this reason, it is sometimes referred to as “molecular photocopying“.

The purpose of Polymerase Chain Reaction testing is to diagnose and monitor hematologic malignancies and solid tumors. Peripheral blood, bone marrow, and paraffin embedded tissue are acceptable specimen types for Polymerase Chain Reaction (PCR) testing. We use Polymerase Chain Reaction at Genetics Associates in the diagnosis, monitoring, and treatment of patients suffering from Leukemia. This is done in the form of targeted cancer therapy.

How does Polmerase Chain Reaction (PCR) work?

Four things are required in the Polymerase Chain Reaction (PCR) cycle. The first is a target sample.  The target sample the patient whose DNA is going to be amplified by the PCR process.

The second requirement is a primer. The primer acts as an adhesive to the target sample and provides a starting point for the amplification process. Basically, it selects the portion of DNA that will be copied.

The third component of the PCR cycle is the Taq polymerase.  This is the enzyme that replicates the DNA.

Lastly, the fourth step in the PCR process is that Nucleotides must be introduced to act as “building blocks” for the new DNA strands.

The Three Steps of Polymerase Chain Reaction (PCR)

Step one is to heat the target sample in order to denature the DNA. Denaturing is the process of unwinding the two strands of DNA into a single strand.

Step two is to reduce the temperature so that the primer can be added. This allows the added molecules to bind, or anneal, to pieces of the single strand DNA. This part of the process “labels” the starting points of segments of DNA that are to be amplified and replicated.

Step three is to create new segments of the single strand DNA. This  is accomplished by adding the Taq polymerase. It moves along the primed segments of DNA in order to create a template for replication as it moves along. Doing this over and over creates a “chain reaction“, hence the name Polymerase Chain Reaction (PCR).

Polymerase Chain Reaction Testing for Leukemia

The results of this testing is determined by Nashville based laboratory, Genetics Associates. All results are interpreted by board certified and Tennessee licensed cytogenetic directors at our laboratory, who are available to discuss results and offer clinical advice. Contact us to learn more about our PCR testing.