What Is Fine Needle Aspiration of the Thyroid?

The thyroid is an important organ in your endocrine system. It releases hormones that regulate many of the functions in your body. The thyroid gland is near the base of the neck, just below the Adam’s apple. Sometimes small nodules, or lumps, appear on the thyroid. When this happens, the doctor may order a test known as fine needle aspiration (FNA), or fine needle biopsy, to obtain tissue samples from the thyroid for analysis.

Your doctor may order this test if you have:

  • a persistent cough, hoarse voice, or unexplained sore throat for a long period
  • nodules, or lumps, on your throat that you can feel or see
  • lumps that are detected on a routine ultrasound
  • a cyst, or fluid-filled lump, on your thyroid

By aspirating, or obtaining tissue from the site, your doctor will be able to see if the lump is cancerous or not. Most of the time, the nodule will end up being a benign, or harmless, tumor. If you have a cyst instead of a nodule, your doctor may perform fine needle aspiration to drain the cyst.

Fine needle aspiration is the only nonsurgical way to find out if any lumps or nodules are benign or malignant.

While the test can be done in a hospital, you may have the procedure done in your doctor’s office. You don’t need to have a special diet or avoid any drinks or medications before the procedure. If you take a blood-thinning medication, make sure to tell your doctor. You may need to avoid taking it and other medications that thin the blood, such as aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs). Avoid wearing necklaces or any other jewelry that may interfere.

If you’re nervous or anxious about the procedure, discuss your concerns with the doctor. It’s important that you are able to lie still for an extended period.

Before the procedure begins, you may need to put on a gown.

When the procedure begins, your doctor will ask you to lie down. You will feel a cold sensation as your doctor cleans your neck with iodine or another solution that kills any harmful germs that may be on your skin. In some cases, your doctor will use a local anesthetic to numb the area, but this isn’t always necessary.

Next, your doctor will insert a small needle into the nodule. You should not talk, swallow, or move while this happens. Your doctor will repeat this a few times to make sure they have a large enough sample for the analysis.

The procedure usually lasts about 20 to 30 minutes. After the procedure, your doctor will place some gauze over the area and apply pressure for several minutes to stop the bleeding. You may see a small bruise on the area within a day or two.

Your doctor may tell you not to take any medications that contain aspirin or nonsteroidal anti-inflammatory drugs for 24 to 48 hours.

Fine needle aspiration of the thyroid is generally safe. Still, there are some risks, such as:

  • bleeding
  • infection
  • cysts

You may experience swelling, bruising, or slight pain, which is normal. Call your doctor if you develop a fever or continue to have swelling or more intense pain.

Your doctor will send your tissue sample to a lab for analysis. The results are usually available within one week. The results that come back will fall into one of four categories:

  • benign (not harmful)
  • suspicious (may be cancerous)
  • malignant (cancerous)
  • inadequate/indeterminate (unable to tell from the sample)

Your doctor will discuss the results with you and determine the next steps to take. If you have suspicious, malignant, or inadequate results, you may need to have further procedures.