The USDA’s Animal and Plant Health Inspection Service (APHIS) last week issued a memorandum providing guidelines for companies wishing to secure USDA licensing for veterinary disease diagnostic kits.

APHIS Veterinary Services (VS) Memorandum 800.73 is available on the Center for Veterinary Biologics (CVB) Web site.  

The memorandum provides guidance to licensees, permittees, and applicants to support an application for a U.S. Veterinary Biological Product License or U.S. Veterinary Biological Product Permit for diagnostic kits intended for the detection of animal disease or immunological status, as authorized by title 9 CFR part 101.2.

In its guidance, APHIS-VS notes that diagnostic kits must be validated to demonstrate the fitness for intended use, meaning they must be reliable, reproducible, and scientifically sound. The formal process for evaluating these kits—including diagnostic performance characteristics—is known as validation. The guidance document outlines an approach for validating a diagnostic test, writing an Outline of Production, and confirming the expiration dating.

Companies do not need a USDA license or permit to market diagnostic tests, but the licensing process provides a means of assuring consistent standards. Back in November 2014, members of the American Association of Veterinary Laboratory Diagnosticians (AAVLD) and U.S. Animal Health Association (USAHA) discussed standardization of the diagnostic process during their annual meetings in Kansas City, Missouri.

 “Diagnostic standards are in place for state and federal regulatory testing, but that represents only a small fraction of the testing done in diagnostic laboratories,” said Dr. Bruce Akey, a veterinarian and director of the Texas A&M Veterinary Medical Diagnostic Laboratory. “U.S. Department of Agriculture (USDA)-approved diagnostics have built-in standardization, but additional steps must be taken to validate and verify results of the other diagnostic tests developed by individual laboratories.”

Relatively new guidelines developed by the AAVLD have given member laboratories a process to follow, and specific criteria for validating and documenting development of new assays. “Previous methods used to validate new diagnostic tests varied widely across the country and throughout the world,” said Johnny Callahan, Ph.D., a senior consultant with Thermo Fisher Scientific, a company with deep expertise in animal diagnostics. “Many laboratories now are making a great effort to base new assays on these guidelines, completing extensive documentation to validate results.”

USDA licensing for some diagnostic tests
With 43 AAVLD-accredited laboratories as well as additional labs conducting numerous types of diagnostic tests, many of which were developed by individual labs, the effort needed to ensure all tests meet agreed-upon standards is huge. That is one reason why more laboratories are using USDA-licensed diagnostic tests to provide consistent, standardized results to their veterinary and producer clients, according to a news release from Thermo Fisher Scientific. “For a diagnostic to receive USDA approval, documentation must prove the assay provides consistent results and meets stringent quality standards,” Callahan says. “Having this information already in place can significantly lessen the documentation burden on AAVLD-accredited laboratories. Beyond that, these diagnostics also meet very high USDA manufacturing requirements, delivering consistency that is difficult for individual labs to achieve when making their own batches of assays.”