The Coggins test is a standard fixture in a routine annual equine wellness appointment. Veterinarians usually pull blood for this test when they perform spring vaccines, but some horse owners may not fully understand why.

Coggins testing is often mandatory if your horse travels for competition or lives at a boarding facility. Many veterinarians recommend that every horse gets an annual Coggins test.

This test is critical for controlling the spread of Equine Infectious Anemia (EIA), a contagious and incurable disease with potentially fatal outcomes. Positive results must be reported to local animal health authorities, and infected horses must be quarantined.

This article will review everything you need to know about the Coggins test for horses and controlling the spread of EIA. Keep reading to learn why this test is vital for protecting the health of every horse on your farm and the biosecurity of the equine industry.

Coggins Testing for Horses

Named after Dr. Leroy Coggins, who developed the test in 1970, the Coggins test is a simple, reliable, and inexpensive way to prevent the spread of infectious disease in horses. [1]

A Coggins test is a laboratory test used to detect the presence of antibodies for equine infectious anemia in blood from horses, donkeys, and mules. These antibodies are present after exposure to the virus that causes EIA. [2]

Veterinarians use this test to diagnose EIA and identify horses as carriers of this transmissible disease. While several tests can screen for EIA antibodies, the Coggins test is the most popular. [2]

Mad About Horses
Join Dr. Chris Mortensen, PhD on an exciting adventure into the story of the horse and learn how we can make the world a better place for all equines.
Apple Podcasts Spotify Youtube
Mad Barn - Equine Nutrition Consultants | Mad Barn Canada

Equine Infectious Anemia

Equine infectious anemia is a bloodborne viral disease that only affects members of the Equidae family. There is no vaccine for EIA, and infected horses become lifelong carriers. EIA is found throughout the world and is a reportable animal disease in the U.S. and Canada. [3]

The virus belongs to the same family of viruses as human immunodeficiency virus (HIV), but EIA is not transmissible to humans.

Testing for EIA

The Coggins test refers to a specific laboratory diagnostic test that uses agar gel immunodiffusion assay (AGID) to detect antibodies in blood serum. Veterinarians can also test for EIA using a competitive enzyme-linked immunosorbent assay (C-ELISA). [4]

The C-ELISA test produces faster results than the Coggins test, but there is an increased incidence of false positives. Horses that get a positive result from an ELISA test need a Coggins test to confirm the findings. [4]

Reverse transcription polymerase chain reaction assays (RT-PCR) can help confirm the diagnosis when tests yield conflicting results. PCR assays are also helpful for detecting viral genetic material in foals born to infected mothers. [5]

Performing a Coggins Test

To perform a Coggins test, equine veterinarians draw blood from your horse to send to an accredited lab for analysis. These labs conduct the test to detect EIA antibodies and provide a positive or negative test result finding to the veterinarians.

A negative result means that the antibody was not detected in the horse’s blood, while a positive result means that antibodies are present. Veterinarians share the results with horse owners in Coggins papers. [2]

Coggins Papers

Horse owners use Coggins papers as proof of negative test results. These results expire one year after the testing date, so annual testing is necessary.

Coggins papers include critical information about the horse’s owner, stable/environment, and veterinarian. The report will also contain information to verify the identity of your horse, such as his name, registration number, breed, age, sex, colour, microchip, pictures, tattooing/branding, and marking descriptions.

A negative Coggins should accompany your horse whenever he travels or moves barns to show that your horse isn’t an EIA carrier.

Positive Coggins Tests

What happ