Updated Information on Equine Infectious Anemia Testing

Sample and Official Form Requirements for EIA Testing

The following guidelines have been issued by USDA/APHIS and they must be followed in order for laboratories to maintain approval for performing EIA testing:

All test kits that are used for testing of horses for infection by equine infectious anemia (EIA) virus must be approved by the USDA’s Center for Veterinary Biologics (CVB). In the licensing process, a manufacturer must submit test performance data to CVB as part of the approval process. Data that is submitted includes the type of samples that were used to achieve the level of test performance reported. This information defines how the test can be used. For example, the test kit information will specify whether for a serological test one can use serum or plasma. If the test kit specifies "serum", then under QA standards, the test is not valid if plasma is used. The definition of what is an "acceptable" sample is a key component of the test kit as approved. USDA/APHIS states that samples should be collected, handled, stored, and transported to the laboratory so they arrive in good condition, in sufficient volume, and free from heat damage, hemolysis, or other degradation or contamination. Samples should be submitted to the laboratory as soon as possible after collection.

For EIA testing, both AGID and ELISA, acceptable specimen is defined by the kit and USDA/APHIS. Serum is the only acceptable sample for the EIA AGID and EIA ELISA kit currently in use at the AHDC.  For EIA ELISA testing the kit currently in use at the AHDC states: "Specimens may be stored at 2-7C for up to twenty one days." The simple interpretation of this statement is that the specimen must be tested within 21 days of sampling if it is maintained at 2-7C (refrigerated) during this period. This does not mean that samples can be shipped on day 21 and meet the kit requirements. For EIA AGID testing the kit currently in use at the AHDC states: "Specimens may be stored at 2-7C for up to twenty eight days." In the past, many labs have ignored this type of restriction on the acceptability of the specimens. However, all laboratories certified by the USDA to perform EIA testing, public and private, are required to follow kit manufacturer's instructions and the issue of the age of the specimen for EIA testing can no longer be ignored. Laboratories are responsible for enforcing the sample requirements and the failure to adhere to the kit instructions can be the basis for losing their USDA license for performing EIA tests.  In addition to kit manufacturer restrictions, USDA/APHIS states that no sample over 30 days old (regardless of whether or not it was frozen) can be tested as test results do not reflect current exposure status of the animal. "Acceptable" sample requirements have not been strictly defined in the past, but failure to adhere to the specimen requirements in the future may result in test delays as "expired/inappropriate" samples will not be tested.

If there are questions as to the acceptability of a specimen, please contact the AHDC before submitting the specimen. Unacceptable specimens can not be returned to the submitter.

As a reminder, only a Category II federally accredited veterinarian, state animal health official or federal animal health official may submit samples for EIA testing. USDA/APHIS strictly prohibits screening or preliminary testing. ALL EIA tests are official and need to be accompanied by an official test form. All information/data points on official test forms must be filled out. If any field is "none," write "none" or line through; do not leave blank fields.  

At the discretion of the laboratory, amended forms can be processed as long as:

  • They are received within 30 days of the draw date of the sample.
  • Previously distributed copies are returned to the laboratory.
  • Change of ownership is not one of the items being amended.

Additionally, EIA test paperwork for all New York State horses tested at any laboratory may be reviewed by Ag & Markets staff to determine the time elapsed between when the sample was taken and when it was tested and to assure completion of all required information.

VIR-WEB-001-V04

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