Fine-Needle Aspiration Biopsy (FNAB)

The thought of a needle is intimidating if not outright frightening. No one wants pain or side effects from procedures. Fortunately, an FNAB is not as bad as it sounds. Here are some details about this procedure.


  • Be sure to wear a shirt that has an open neck.
  • Remind the doctor of any medications you are taking such as blood thinners or aspirin. You will be told if and when you need to stop taking them and for how long.
  • Acetaminophen is usually all right to take.
  • Most doctors give their patients an information packet to explain all there is to know. If you do not get one, be sure to ask about any concerns you may have.
  • Have ice packs available at home for if there is any swelling to the procedure site.

What to Expect:

  • First of all, you will read and then sign a consent form.
  • If you forget to wear a shirt with an open neck, you will need to remove it and put on a ‘hospital’ gown.
  • You will be asked to lie down on the examining table with a towel under your neck and to put your head back as far as is necessary for the doctor to have good access to your throat.
  • General anesthesia is not required.
  • The neck is cleaned with alcohol and then an iodine solution to lower risk of infection.
  • You will then have an injection of 1% xylocaine into the skin over the nodule. This causes a brief stinging sensation, but it numbs the area to make the procedure tolerable.
  • The doctor will use ultrasound equipment to assist in accurately locating the nodule. 

Now is the time to point out that the needle they use is smaller than the needle used to draw blood. Also, most people have reported either no pain or a slight pinch, and that it is less painful than the procedure to draw blood. If the nodule is in the front of your neck or not by a vein, you can breathe and swallow normally. Some mild pain may be experienced if the nodule is deeper inside the thyroid, and you will be asked to hold your breath, not move, and to not swallow for the brief time the needle is injected.

  • There can be up to 5 needle passes to collect enough cell samples.
  • The samples are placed on slides for a pathologist to examine.
  • Now they will clean your neck and apply a small adhesive bandage over the site.
  • You are asked to sit still for awhile afterwards, and that’s it. The procedure is finished.
  • A follow-up appointment is made to discuss the results and treatment plan.

Any Complications After?

  • It is very, very uncommon for an infection to develop at the biopsy site.
  • Significant bleeding is also rare.
  • It is uncommon for bleeding to occur into the biopsied nodule. Swelling of the nodule or pressure in the area of the biopsy is a symptom of bleeding and should be reported to the doctor.
  • Some light bruising is reported by most patients and is normal.
  • Mild discomfort or tenderness is also normal and resolves after at least 24 – 48 hours.
Waiting for Results:
  • On average, it takes 7 days.
  • Do not expect to get the results over the phone. The results need to be discussed fully at the follow-up appointment.

Now that the procedure has been done, the next step is finding out the results and what they mean. Read on to find out more.

Thyroid Nodule Fine Needle Aspiration (graphic)

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