The diagnostic service dates from 1892. In 1914, the service was carried out in the Department of Pathology and Bacteriology. In 1917, it was transferred to the Department of Veterinary Investigation, which was later housed at the State Biological Laboratory. In 1928, the diagnostic laboratory was moved to the basement of the building occupied by the Department of Veterinary Pathology and became a function of that department. In 1934, a Federal laboratory for the blood testing of cattle for brucellosis was established in the basement of the Veterinary Administration building. In 1946, the Veterinary Diagnostic Laboratory was established with E. A. Benbrook as supervisor. A separate facility was dedicated in 1956. In 1997, the Veterinary Diagnostic Laboratory combined with Production Animal Medicine and Veterinary Medicine Extension.

Collection consists of case log books for the Veterinary Diagnostic Laboratory. Access to the books is restricted to the following people: Gary Osweiler and Connie Hodenfield. Anyone else must have approval from the Director of the Department of Veterinary Diagnostic and Production Animal Medicine.

Collection is arranged chronologically.