Polymerase Chain Reaction: Benefits and Drawbacks

The application of polymerase chain reaction (PCR) assays to veterinary medicine has revolutionized the way diagnosticians detect infectious agents and genetic markers of non-infectious disease. Confusion frequently encircles this technology due to its novelty and complexity. This article will briefly review the underlying basis of PCR, describe interpretation of results, and discuss its ben

Share
Favorite
Close

No account yet? Register

ADVERTISEMENT

The application of polymerase chain reaction (PCR) assays to veterinary medicine has revolutionized the way diagnosticians detect infectious agents and genetic markers of noninfectious disease. Confusion frequently encircles this technology due to its novelty and complexity. This article will briefly review the underlying basis of PCR, describe interpretation of results, and discuss its benefits and drawbacks over traditional methods of pathogen detection.

All living organisms contain unique sequences of genetic material that consist of deoxyribonucleic acid (DNA) and/or ribonucleic acid (RNA ). These hereditary materials serve as templates (or codes) for cellular reproduction and orchestrate the construction of proteins that are essential to all biologic processes. Traditional methods of pathogen recognition (i.e., bacterial culture, fluorescent antibody tests, serologic tests, etc.) have focused on the presence of proteins for identification. Conversely, PCR tests are designed to amplify and detect segments of DNA or RNA that are very specific to a genetic sequence or organism.

Interpretation of positive and negative PCR results can be challenging. Similar to traditional pathogen detection techniques, PCR results must be strictly interpreted in conjunction with the history, clinical signs, and evidence of disease. A positive PCR result only indicates the detection of the target genetic sequence. It can not differentiate between the incidental presence of an organism, colonization without disease, transient infection, or active infection with disease.

In addition, a positive PCR test can't differentiate between living or dead organisms as genetic material can be present in both. Assays can be designed to differentiate pathogenic from nonpathogenic isolates but may not distinguish between vaccine strains and wild-type pathogens. Knowledge of the vaccine (modified live versus killed; route of inoculation; and duration of vaccine persistence) in combination with clinical disease can greatly aid in the interpretation of whether a positive PCR is due to vaccine interference or vaccine failure. Equally important, false negative PCR results may arise due to PCR inhibitors found in clinical samples. Newer technology has greatly eliminated the influence of these inhibitors on PCR results

Create a free account with TheHorse.com to view this content.

TheHorse.com is home to thousands of free articles about horse health care. In order to access some of our exclusive free content, you must be signed into TheHorse.com.

Start your free account today!

Already have an account?
and continue reading.

Share

Written by:

Related Articles

Stay on top of the most recent Horse Health news with

FREE weekly newsletters from TheHorse.com

Sponsored Content

Weekly Poll

sponsored by:

Where do you primarily feed your horse?
282 votes · 282 answers

Readers’ Most Popular

Sign In

Don’t have an account? Register for a FREE account here.

Need to update your account?

You need to be logged in to fill out this form

Create a free account with TheHorse.com!