# Coggins test for horses: what it is, how often and what papers you need > What the Coggins test checks for, who needs one and how recent it must be for sales, events and travel, with the Texas and California rules as examples, and how to keep the papers where you can find them. Canonical: https://lucernel.com/guides/horse-coggins-test Last updated: 2026-10-29 Type: Guide. Publisher: Lucernel. ## Short answer A Coggins test is the blood test for equine infectious anemia (EIA), a viral disease with no treatment or vaccine. USDA recommends testing every horse yearly, and Texas and California both ask for a negative result from within the last 12 months in the situations they cover, but rules differ by state and event, so check the destination before you haul. - **Choose this if:** Read on for who needs the test, how recent it must be, what the paperwork shows and how to keep it at hand. - **Choose the other option if:** Trotley keeps the Coggins papers and the lab report with the horse, next to the vaccination and vet records you may be asked for at the same gate. ## Side by side | | Texas | California | | --- | --- | --- | | When a negative test is required | Change of ownership; any assembly such as a rodeo, trail ride or parade; pari-mutuel tracks; public riding trails; boarding, training or breeding facilities | Entry into the state | | How recent | Within the previous 12 months | Within 12 months before entry, from a USDA approved lab | | Age exceptions | Change of ownership applies to horses 8 months or older; other exceptions exist | Nursing foals under 6 months moving with a test-negative dam | | Pending results | Not stated in the fact sheet | Not accepted | | Papers | VS 10-11 form, “Coggins papers”, kept on hand when traveling | The certificate of veterinary inspection (CVI) must list the sample date, lab, accession number and result | ## What EIA is and what the test finds Equine infectious anemia is a viral, sometimes fatal disease that affects only horses, ponies, mules, donkeys and zebras, according to USDA APHIS. There is no treatment, it is found in nearly all countries including the United States, it is a reportable disease in every state and it is not a threat to human health. Signs such as fever, poor appetite and anemia can be mild or severe, and chronically infected horses may show no signs at all. Carriers can also have flare-ups, often after stress or strenuous work, which is why a horse that looks healthy still needs the test. The Coggins test is the laboratory assay that has been used to detect and control EIA in the United States since the 1970s. APHIS says it may take 60 days or more after infection for a horse to test positive, so one negative result is a snapshot, not a lifetime clearance. ## Why states and events ask for it Infected horses that survive become carriers and can infect other horses for life. APHIS says they must be euthanized or permanently isolated. Biting flies such as horseflies and deerflies can spread the virus, and so can needles, syringes and instruments reused between horses. APHIS says that human-facilitated spread is now the most common route in the United States, especially among current or former Quarter Horse racehorses. APHIS reports that since its control efforts began in 1972, estimated national prevalence has fallen from nearly 4% to 0.004%. Its advice to owners is to test every horse, pony, mule and donkey annually. ## Who needs one, and how recent it must be The rules are set by each state and by event organizers, so the table above is an example, not a national rule. Texas requires a test within the previous 12 months for a change of ownership of any equine 8 months or older, and for horses at assemblies, pari-mutuel tracks, public equestrian trails and boarding, training or breeding facilities. The Texas fact sheet makes the event or stable responsible for checking that each horse has a valid VS 10-11 document. California requires evidence of a negative test from a USDA approved laboratory within 12 months before entry, with exemptions for nursing foals under 6 months with a negative dam, and it does not accept pending tests. For any other state, CDFA points owners to the USDA interstate travel page and to InterstateLivestock.com, and advises calling the destination state. Our advice: check the destination and the event before you plan the trip, since California does not accept a pending result. ## The papers: what to carry A veterinarian draws the blood and sends it to an APHIS-approved laboratory. APHIS says accredited veterinarians submit samples with a VS 10-11 form, and the Texas fact sheet calls the document issued to the owner “Coggins papers”, the official proof of testing, to be kept on hand when traveling. California’s entry rules also require a CVI issued within 30 days of movement, and the CVI must list the sample date, the lab, the accession number and the result. We did not find a state or USDA figure for what the test costs. The fee is set by the veterinary practice, so ask when you book, along with any farm call charge. ## If a test is positive Call your veterinarian if you suspect EIA in any horse. APHIS says to move a suspect horse at least 200 yards from other equids and that confirmed cases must be permanently isolated or euthanized. In Texas, every equine on the shared premises or exposed to the horse is quarantined and must be tested. These decisions belong to your vet and your state animal health officials. ## Keep the papers in one place Ours is a simple habit: when the papers arrive, photograph them, store the file with the horse and set a reminder for about 11 months out, so renewal does not fall on the week of a show. Keep a paper copy in the trailer, as the Texas sheet advises, and send a copy to the barn manager if you board. Disclosure: Trotley is made by Lucernel, the publisher of this article. ## Frequently asked questions ### What is a Coggins test? A blood test for equine infectious anemia, a viral disease with no treatment or vaccine. USDA says it has been the diagnostic assay for EIA control in the United States since the 1970s. ### How often does a horse need a Coggins test? USDA recommends testing annually. Texas and California ask for a negative result from the previous 12 months in the cases they cover, and other states and events may differ. ### What are Coggins papers? The VS 10-11 form a veterinarian issues as official proof of the test. Texas says to keep it on hand when traveling. ### Do foals need a Coggins test? It depends on the state. California exempts nursing foals under 6 months moving with a test-negative dam, and Texas applies its change-of-ownership rule to horses 8 months or older. ### Is Trotley available? See the official app page for current availability and pricing. ## Our pick: Trotley, the papers stay with the horse A Coggins result is only useful if you can produce it at the gate. Trotley stores passports, papers and photos with each horse, keeps vaccination and vet events on the same record, shows what is due on a stable calendar with reminders, and works without a connection at the show grounds. It does not know your state’s rules, so check those with the destination and your vet. - Papers and lab reports stored with the horse - Reminders rebuilt from your records - Works offline, with a PDF report for the vet [See how Trotley works](https://lucernel.com/apps/trotley) ## Sources (checked 2026-10-01) - [USDA APHIS: Equine infectious anemia](https://www.aphis.usda.gov/livestock-poultry-disease/equine/infectious-anemia) - [Texas Animal Health Commission: Equine infectious anemia fact sheet (revised August 2021)](https://www.tahc.texas.gov/news/brochures/TAHCFactsheet_EIA.pdf) - [California Department of Food and Agriculture: Equine entry requirements](https://www.cdfa.ca.gov/AHFSS/Animal_Health/pdfs/EquineEntryRequirements_FactSheet.pdf) - [California Department of Food and Agriculture: Entry requirements](https://www.cdfa.ca.gov/ahfss/Animal_Health/Entry_Requirements.html)