Failure to pass the initial and re-screening of hearing screening requires referral to the Children’s Hearing Diagnostic Center at 2-3 months of age for a comprehensive diagnostic hearing examination to clarify the nature and extent of hearing loss. Specific tests include: Auditory Brainstem Response (ABR, including air and bone conduction thresholds), Distortion Product Otoacoustic Emission (DPOAE), Auditory Steady-State Response (ASSR), and 1000 Hz acoustic impedance. Clinically, it is necessary to analyze the results of each of the above tests in order to determine the nature and extent of hearing loss, rather than relying solely on the results of ABR.