Immune inner ear disease is a relatively new and distinct clinical entity that produces unexplained, rapidly progressive, bilateral sensorineural hearing loss. The diagnosis is based on clinical manifestations, positive immune laboratory testing, and beneficial response to a trial of corticosteroids. Immune laboratory tests are used to confirm a presumptive clinical diagnosis. The two tests most commonly used are the lymphocyte transformation test and Western blot immune assay. The rationale behind these tests is presented, and the role they play in laboratory diagnosis of immune inner ear disease is discussed.