The comparative cervical test (CCT), or any other test approved by the USDA, is the official tuberculin test for retesting of suspects. It shall be conducted only by a full-time state or federal regulatory veterinarian and shall not be used in known infected herds without the prior consent of cooperating state and federal officials. The CCT shall not be used as a primary test for animals of unknown status.
Okla. Admin. Code § 35:15-40-35