Prior to thyroid surgery, various tests may be performed to ensure that a patient is a good candidate for the procedure. The physician typically begins by reviewing the medical history and performing a physical examination. Patients who are older than 45 or who have a history of heart disease may be evaluated with tests such as an electrocardiogram (EKG) and a chest x-ray. For thyroid nodules, a fine-needle aspiration biopsy is the primary means of distinguishing cancerous growths from benign ones.

Other tests that may be performed prior to the procedure include:

• Evaluation of vocal cord function. This may be recommended for patients who have experienced a change in their voice or who have had a previous neck operation. Such testing may include indirect laryngoscopy (simple examination involving mirrors and a bright light) or direct laryngoscopy (insertion of a flexible fiber-optic scope into the throat). In addition, laryngeal nerve function may be assessed with tests such as electromyography or a nerve conduction velocity test.
  
  
• Blood tests. These may be performed for various reasons, such as checking for the presence of a bleeding disorder, or screening for hypercalcemia due to parathyroid disease (which is sometimes present in people with thyroid disorders).
  
  
• Tests for coexisting conditions. Patients who have conditions such as medullary thyroid cancer (rare cancer often associated with other endocrine problems) may undergo testing for other conditions such as coexisting adrenal tumors (pheochromocytomas), hypercalcemia and hyperparathyroidism.