If your child has been diagnosed with hearing loss in the hospital after a newborn hearing screening session and has failed both the initial and repeat screening results, then active treatment intervention is required. If the doctor says that medication or surgery is not an option, your child should be fitted with a hearing aid and, if necessary, a cochlear implant within six months of age. For children who pass the screening test, but suspect abnormal hearing behavior and response as they grow up, a diagnosis should be made at the hospital immediately. The first step is to get a special or specialist hearing appointment. During the visit, the doctor will ask you about your child’s medical history that has a significant impact on hearing, and a careful physical examination of the ear, nose and throat. A combination of audiological tests will be prescribed and, if necessary, special imaging and laboratory tests will be ordered. When all the test results are reported, the doctor relies on these reports to make a comprehensive diagnosis and hearing evaluation for your child, and finally to recommend an intervention plan such as audiology. With the information obtained through history taking, general and local physical examinations, various audiological tests, imaging and laboratory tests, the doctor can make a comprehensive assessment of the infant’s hearing loss, whether it is monaural or binaural, the degree and configuration of the hearing loss, and the integrated function of the entire auditory system, and can then expect to make a qualitative/local, quantitative and etiological diagnosis of the hearing loss, although an etiological diagnosis is sometimes difficult to achieve. 1. Qualitative diagnosis 1. Qualitative diagnosis: usually a distinction is made between conductive, sensorineural, neurological and mixed hearing loss. Conductive hearing loss is often an external or middle ear lesion, sensorineural hearing loss is a cochlear lesion, neurological hearing loss is a post cochlear lesion, and mixed hearing loss is a multi-site lesion. Therefore, qualitative diagnosis is actually diagnostic localization, and clarifying the nature and location of hearing loss is of great significance in choosing a treatment plan. Through comprehensive examination, especially ear, hearing and imaging examination, it is generally not difficult to determine such diagnosis. 2. Quantitative diagnosis: quantitative diagnosis is to quantify the degree of hearing loss, so as to choose the appropriate treatment/intervention plan. Hearing loss. 3. Etiological diagnosis: Data show that more than half of the congenital deafness group is caused by genetic factors. In other words, environmental and genetic factors account for about half of the etiology of congenital hearing loss. Therefore, the first step in the diagnosis should be to try to figure out which factor is the cause or both. In the case of hereditary, it should be clarified whether it is syndromic (about 30% of cases) or non-syndromic (about 70% of cases). In the case of environmental factors, the presence of bacterial or viral infections, ototoxic antibiotics and other environmental toxin effects, as well as physical and acoustic trauma should be clarified. Etiological diagnosis of most infants and children with hearing loss can be made through history taking and thorough examination, especially genetic and viral testing.