The test is performed in a hospital operating room using general anesthesia. You will likely be given an injected sedative about one hour before the procedure. An intravenous (IV) line is placed in a vein, usually in your arm.

Throughout the procedure, you are given a mixture of anesthetic gas and oxygen through a hollow tube that is inserted through your mouth and into the trachea.

A small incision is made in your neck .Usually either one half of the thyroid or a thyroid lump is removed.

The sample is sent to the laboratory to be examined while you are still on the operating table. The results of this study may determine the need for further removal of thyroid tissue.

The incision is then stitched closed.

Inform the doctor of any drug allergies you have, which medications you are taking (including any herbal remedies), if you have bleeding problems, and if you are pregnant.

You must sign a consent form. You will be asked not to eat or drink for 8 to 12 hours before the biopsy.

Infants and children:
The physical and psychological preparation you can provide for this or any test or procedure depends on your child's age, interests, previous experience, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child's age:

• Infant test or procedure preparation (birth to 1 year)
• Toddler test or procedure preparation (1 to 3 years)
• Preschooler test or procedure preparation (3 to 6 years)
• Schoolage test or procedure preparation (6 to 12 years)
• Adolescent test or procedure preparation (12 to 18 years)

You may feel a prick when the sedative is injected. When you wake up after the procedure, you will feel drowsy for several hours. You may have a mild sore throat from the tube. There will be some discomfort from the biopsy site.

The thyroid tissue is normal in structure and no cancer is found on microscopic examination of the thyroid gland.

Abnormal results may mean thyroid cancer, a noncancerous tumor, or diffuse thyroid disease.

Additional conditions under which the test may be performed include the following:

• Anaplastic carcinoma of the thyroid
• Medullary carcinoma of thyroid
• Multiple endocrine neoplasia (MEN) II
• Painless (silent) thyroiditis
• Papillary carcinoma of the thyroid
• Subacute thyroiditis

The main risk is bleeding into or around the thyroid gland. If severe, emergency drainage may be required in order to prevent airway compromise. Rarely, injury to the nerves that innervate the vocal cords can occur, which can cause a hoarse voice. Injury to the parathyroid glands can also occur, which may cause alterations in calcium metabolism.