Generally, when thyroid nodules are detected, one should visit the hospital's breast and thyroid surgery department or the endocrinology department. If you find a thyroid nodule, you can consult a doctor and undergo some relevant tests based on your specific situation. Typically, the following tests are conducted: 1. Thyroid ultrasound: This can determine the size, number, location, texture, shape, and edges of the nodules, including whether there is calcification. It also examines the blood supply within the thyroid nodule, the relationship with surrounding tissues, and assesses whether there are lymph nodes in the neck and the nature of these lymph nodes. 2. Blood tests are needed to measure thyroid function, particularly the level of Thyroid Stimulating Hormone (TSH). Higher levels of TSH indicate that the thyroid nodule is more likely to be proliferative, and thus, the risk of thyroid cancer increases. In addition, Thyroglobulin (Tg) can be measured. Another measure is Serum Calcitonin (Ct). If serum calcitonin is > 100 pg/mL, medullary thyroid cancer should be highly considered, as these cancer cells can secrete large amounts of serum calcitonin, causing this marker to significantly increase. Nuclear isotope imaging is also performed. If the nodule is large and TSH levels are low, a thyroid radionuclide scan is conducted to see if the nodule is a hyperfunctioning adenoma. When necessary, a Fine Needle Aspiration Biopsy (FNAB) is also performed. Fine needle aspiration is an invasive test, but it is currently an important and most efficient method to assess the benign or malignant nature of the nodule. It is generally performed under ultrasound guidance.