Understanding thyroid cancer tests
Penn Medicine specialists use different thyroid tests to diagnose cancer. We start with a physical exam and talk with you about any family history of thyroid cancer.
Our experts may recommend one or more of the following tests.
A thyroid ultrasound is an imaging test that uses high-frequency sound waves to create detailed pictures of your thyroid. It’s the best imaging test to evaluate a nodule’s size, borders, and internal tissues.
Ultrasound can help your care team see:
- Nodules that have features indicating cancer
- Benign nodules (nodules that aren’t cancerous)
- Nodules that are too small to feel
- Whether a nodule is growing or staying the same over time
Using ultrasound, your endocrinologist and radiologist determine whether they need to do more testing of the nodule. Our specialists use the standardized Thyroid Imaging Reporting and Data System (TI-RADS) to assess and assign a score to thyroid nodules.
Every thyroid nodule receives a score of 1 (no evidence of cancer) to 5 (cancer is highly likely), depending on how it looks on ultrasound. We look at the nodule’s edges (margins), consistency, shape, and other features to determine its score.
Using TI-RADS scores, we recommend additional tests only on nodules that pose a risk of cancer. This means you avoid unnecessary tests and can feel more confident about your thyroid health.
Depending on your ultrasound results, we may recommend a thyroid nodule biopsy, the most accurate way to diagnose thyroid cancer. During this procedure, a small sample of cells is taken from a nodule and examined under a microscope.
Our specialists perform a fine needle aspiration (FNA) biopsy, which is minimally invasive. Using ultrasound guidance, a thin needle is inserted into the nodule to collect cells. The entire process is typically quick. A pathologist then examines the sample to determine if cancer is present.
If cancer is confirmed, we may take samples of thyroid cancer cells to learn more about their genetic makeup. Our experts use what they learn about a tumor’s genetic changes to develop a systemic therapy treatment that’s appropriate for your type of thyroid cancer.
Our specialists either inject or have you swallow a small amount of radioactive iodine. Your thyroid gland—and any thyroid cells in your body—absorbs this material and makes cells visible during an imaging test. We may use radioiodine testing to see if thyroid cancer has spread.