What is a Coggins test?

The Coggins test identifies horses carrying equine infectious anemia (EIA), a viral disease spread through blood-to-blood contact. A veterinarian draws blood from the horse's jugular vein, and the sample is sent to a lab where technicians use an agar gel immunodiffusion method (AGID) to detect EIA antibodies. Results come back as negative, positive, or inconclusive.

This test matters because EIA-positive horses pose a transmission risk to other horses. Most states require a negative Coggins certificate before a horse can cross state lines or enter a new facility. Many boarding barns in the Denver area make it mandatory for new arrivals, and buyers typically expect a clear Coggins before purchase. The certificate itself is valid for one year from the test date, though some venues request more frequent testing.

Horses that test positive face strict isolation rules and cannot be moved to new locations without state veterinary board approval. While there is no cure for EIA, an infected horse can live for years without showing symptoms. This is why the Coggins test remains the gold standard for identifying carriers.

Veterinarians offering equine services in Denver can draw and submit samples. Having current Coggins results on file is a practical necessity for any horse owner who travels, shows, or boards their animal.