510 ILCS 30/1.3

The term "official test" means any test for the detection of bovine brucellosis, approved by the Department and the United States Department of Agriculture, which is based on the use of a standardized suspension (antigen) of Brucella microorganisms in dilution of blood serum taken from the animal to be tested, a bacteriological culture of brucella abortus from milk or tissue samples or any other test approved by the Department.