What is a PCR Test?
In 1983, Kary Mullis Had a breakthrough about how to develop a way to amplify (make more identical copies) DNA to make huge amounts of copies of a particular DNA sequence. This technique is used in many applications around the world. Some of those techniques include cloning, diagnosing hereditary diseases, parentage testing and in our case, for cats testing for infectious diseases and parasites. We call it a PCR test and it stands for polymerase chain reaction.
Responsible Breeders depend on a PCR test to determine the health of a kitten
The key to understanding PCR is to know that every human, animal, plant, parasite, bacterium, or virus contains genetic material such as DNA or RNA sequences that are unique to their species. In addition, individual members of a species have DNA that is unique to them. DNA transfers from parent to child; half from the mother and half from the father. When we speak of Feline PCR testing sample it is blood, stool, skin scraping, hair, a cheek swab or throat swab.
Once the PCR process begins, a specific process called amplification begins.
- Denaturation, the DNA heats to 194 degrees F to separate the DNA into two strands.
- Annealing, a pcr test is specific to the disease it is looking for. Therefore, each disease or parasite has a primer that binds to the DNA strands. Then the DNA cools to about half the temperature it was in Step 1. When step 2 is complete the lab has two separate strands of DNA. Then, the sequences marked by primers and ready to begin again.
- The extension begins again. The temperature rises again. This time to 161.5 F. Starting where the primers marked DNA Polymerase (enzymes that produce copies) is added. After the completion of ‘extension,’ there are two identical copies of the original DNA.
- The cycle starts over. Each time doubling the exact copies of the original DNA. After thirty to forty cycles more than one billion copies of the original DNA have been made.
The entire process is automated and completes very quickly.
PCR amplification is only part of the identifying test, however. Once the amplification completes, the amplified segments are compared to other nucleotide segments from a known source (for example, dna from giardia).
There is Feline PCR test available for the following diseases and parasites at labs in the United States and Europe.
- Calici Virus
- E. Coli
- Feline Corona Virus
- Immunodeficiency Virus
- Feline Infectious Peritonitis
- Feline Leukemia Virus
- Herpes virus
The benefits of a PCR test includes a lower chance of false negative results and early detection of infections. In addition, PCR tests are highly sensitive since they differentiate pathogen strains that appear similar.