Thyroid Fine Needle Aspiration Biopsy: What You Need to Know

Thyroid Fine Needle Aspiration Biopsy: What You Need to Know

Thyroid nodules are clumps of soft tissues within the thyroid gland. In rare cases, they can be cancerous or interfere with the proper functioning of the thyroid. In such cases, the nodules need to be treated. At UVA, interventional radiologists perform fine needle aspiration biopsy (FNAB), an image-guided procedure to diagnose thyroid growths.

What are Thyroid Nodules?

The thyroid is a butterfly-shaped gland in your neck. It’s responsible for controlling hormones that regulate metabolism. These hormones affect heart rate, brain function, and other necessary bodily processes.

Sometimes, thyroids develop growths called thyroid nodules. Thyroid nodules are very common: about 50% of people will have thyroid nodules by the time they are 60. These growths usually don’t cause any symptoms and are generally benign. In rare cases, thyroid nodules are cancerous and require medical intervention.

In most cases, the most common form of treatment for thyroid nodules is “watchful waiting.” During watchful waiting, doctors and patients work together to monitor the nodule with regular checkups. If it grows, starts exhibiting symptoms, or if levels of thyroid hormone go up, doctors move to treat it quickly.

In the event that a nodule needs treatment, your doctor may present you with different treatment options. Common treatments include medication and surgery, but will vary from patient to patient.

Diagnosing Thyroid Nodules

When present, a nodule is usually identifiable as a lump on one side of the neck near the Adam’s apple. If you think you have a thyroid nodule, feel your neck in this area: if you feel a bump, it could be a nodule.

If you think you have a thyroid nodule, you should schedule an appointment with your primary care doctor. Your doctor will perform a physical exam and check for any signs of a thyroid nodule. If they observe a bump that could be a nodule, the next step will be to run some tests to make an official diagnosis.

There are four ways your doctor may test for thyroid nodules. These are blood tests, ultrasound, radiology scans, and fine needle aspiration biospy (FNAB).

An infographic with 4 of the main ways doctors check for thyroid nodules

Blood Test

Blood tests for thyroid nodules test for both thyroid hormones. An abnormal level of hormones could signal that the nodule is causing hormonal issues.


Ultrasound creates images of the inside of the body using high-frequency sound waves. Your doctor may order an ultrasound of the bump to determine if it is a thyroid nodule.

Radiology Scans

Depending on the nature of the nodule, your doctor may order a CT, MRI, or PET scan.

A CT scan uses x-rays to create sectional scans of the thyroid. MRI uses magnetic fields and radio waves to create images of the thyroid. A PET scan uses radioactive tracers to help make images of organs and tissue more visible.

Fine Needle Aspiration Biopsy (FNAB)

Using ultrasound to create an image of the growth, an interventional radiologist uses a small needle to extract a cell sample from the nodule. This sample is tested for cancer and abnormal levels of thyroid hormones, both of which can be warning signs of a thyroid condition.

The Advantages of Fine Needle Aspiration Biopsy (FNAB)

Thyroid FNAB Icons

Fine needle aspiration biopsy (FNAB) may sound intimidating, but it’s a simple, safe, and effective procedure to determine the nature of a thyroid nodule.

If one of the other diagnosis methods is indeterminate, or if your doctor determines you are at a higher risk for thyroid cancer, FNAB may be the best option for you.

The advantages of FNAB are clear:

  • It’s a highly accurate method of determining if a thyroid nodule is cancerous or not (95% accurate).
  • It’s quick and simple to perform, usually lasting only 10-15 minutes.
  • It’s minimally invasive and non-surgical.
  • It doesn’t require general anesthesia – only a topical anesthetic is used.
  • Recovery time is minimal – most people are back to their normal activities after 48 hours.

During the procedure, a radiologist uses ultrasound to capture a real-time image of the thyroid nodule. They guide a very fine (thin) needle to the nodule and take several tissue samples, which help aid the accuracy of diagnosis. The needle is so thin that Lidocaine, a topical anesthetic, is the only anaesthesia used.

Most patients have minimal discomfort after the procedure. Some may experience pain and discomfort for about 48 hours after the biopsy. Post-procedure discomfort is usually managed with over-the-counter pain medications.

After the procedure, your doctor will send samples to a lab to be evaluated by doctors called pathologists. They will determine the exact nature of the nodule.

Fine Needle Aspiration Biopsy (FNAB) at UVA Health System

At UVA Health System, FNAB is performed by interventional radiologists. These are doctors who perform minimally invasive procedures using medical imaging to provide real-time views inside their patients’ bodies.

FNAB is one of the most accurate ways to diagnose thyroid nodules. If you believe that you or a loved one has thyroid nodules, contact your care provider. Or speak with one of the professionals at the UVA Cancer Center today to start the screening process.

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