The first point is the diagnostic process for differentiated thyroid cancer. Initially, most patients may not have symptoms, while a minority might show symptoms due to invasion of surrounding organs. Ultrasound examination is the preferred method for diagnosing thyroid nodules. Ultrasound can clarify the number, nature, and location of thyroid nodules, as well as provide information on whether there are abnormally enlarged lymph nodes in the neck. It has a relatively high accuracy in identifying the nature of thyroid nodules. Currently, the most accurate test for determining the nature of thyroid nodules remains the fine needle aspiration cytology, which has a diagnostic sensitivity of 83-92% and specificity of 80-92%, but it is not 100% conclusive. The second point is about the diagnosis of medullary thyroid cancer. Besides the tests common for thyroid cancers, additional tests for medullary thyroid cancer can include fine needle aspiration, ultrasound, and some serological tests, such as calcitonin and carcinoembryonic antigen tests.