United States Department of Agriculture Veterinary Biological Product Code Number

A Product Code Number (PCN) assigned by the Animal and Plant Health Inspection Service (APHIS)'s Center for Veterinary Biologics (CVB) to veterinary biological products such as vaccines, bacterins, antibodies, diagnostic products, antitoxins, bacterin-toxoids, and toxioids approved for veterinary use by the United States Department of Agriculture Veterinary (USDA). A quarterly release, as PDF, can be found [here](https://www.aphis.usda.gov/sites/default/files/currentprodcodebook.pdf). The PDF document states (verbatim): The alphanumeric system used for product codes provides for a six-digit number of number-letter combination to be assigned to each product, i.e., the first digit denotes product types; second and third, group by agents; fourth, the viability of vaccine, (live, killed, modified live, etc.); fifth, substrates; and sixth, miscellaneous variables