How well does a thyroid ultrasound tell if you have cancer or not?

Pretty good: The thyroid ultrasound does not directly tell you if you have cancer. The ultrasound identifies suspicious areas of the thyroid. Then, if the areas are suspicious enough, you may undergo a biopsy where a needle is placed into the thyroid area and samples are examined under a microscope to see if you have thyroid cancer or not.

Not: Shows features of the nodules. Need biopsy to see if cancerous. Easy test. I perform hundreds of these biopsies a year.