Final answer:
The control used in SICCT testing is a saline solution.
Step-by-step explanation:
The control used in SICCT (Single Intradermal Comparative Cervical Tuberculin) testing is a saline solution. SICCT testing is used to detect tuberculosis infection in animals, particularly cattle. In this test, a small amount of tuberculin solution is injected into the skin of the animal, and a control injection of saline solution is also given.