The negative group must be re-tested every 30 to 60 days until new cases fail to appear. At that point, those that have not tested positive are regarded as safe. Federal law does not require Coggins tests prior to the interstate movement of horses. It does prohibit the interstate movement of an EIA reactor except to a slaughterhouse, research facility, or home farm of the horse. Any such horse moved from state to state must, by federal law, be identified as an EIA reactor by brand, freezemarking or lip tattoo.
State laws vary from state to state.
Most states require a health certificate before a horse can be brought into the state. Usually, this requirement includes a negative Coggins certificate. Most states require that the test be within 12 months of entry, but a few states require more recent tests, such as 60 or even 30 days. In 1995, a woman was convicted and fined for transporting horses into Ohio without the required EIA certificates. In addition to the criminal penalties, her horses were quarantined for 30 days at her expense in another state.