Coggins test

Coggins Tests


What is a Coggins Test?

A Coggins test is a blood test identifying if a horse is a carrier of Equine Infectious Anemia, a viral disease found in horses. An annual negative Coggins test is required for all travel between states and at most equine facilities. To perform a Coggins test, a licensed veterinarian must draw blood from your horse and send it to an accredited lab for analysis of the presence of antibodies to Equine Infectious Anemia. They will then provide either a positive (antibody is present) or negative (antibody is not present) test result back to the veterinarian, who will share it with the horse owner. These results, often referred to as Coggins papers, will then be available as either a paper or electronic certificate and should be kept with the horse’s health records. The test results expire one year from the testing date.

What is Equine Infectious Anemia?

Equine Infectious Anemia is a bloodborne viral disease that can affect all equids. This virus is of great concern for the horse industry and there is currently no treatment or vaccine for it. Horses with EIA have varying symptoms and prognosis. Acute symptoms often include a fever, disorientation, and weight loss. Rapid death has also been reported for some horses with EIA. Most often, horses with EIA are asymptomatic carriers, showing no signs or symptoms, which is one of the reasons testing is so important. Horses positive for EIA are life-long carriers and pose a risk to any other horse they may be around. Therefore, EIA carriers must be permanently quarantined, being kept at least 200 yards away from other horses, or be euthanized.

Transmission of EIA

Most often EIA is transmitted by biting flies; tabanids (horse and deer flies) are considered the most significant transmitters. Biting flies transmit EIA by taking a blood meal from an EIA carrier and then transmitting that infected blood to a non-infected horse. Since it is relatively impossible to eliminate blood-sucking insects around horses, there is always the potential of a horse contracting EIA (and other bloodborne diseases) when in the vicinity of an infected horse. Other modes of transmission of EIA include use of contaminated equipment, such as used needles and syringes, mare to foal transmission in-utero, and through natural breeding of mares and stallions.


Obtaining a Coggins test annually is imperative to reduce risk of EIA transmission. As most carriers of EIA are asymptomatic, testing can help identify carriers and prevent transmission to other horses. Any time you plan to travel with your horse, make sure you explore documentation requirements for that state, facility, and event before departing. Additionally, make sure that a current negative Coggins is available for any horse you plan to purchase or sell.