Fine Needle Aspiration (FNA)

April 1, 2026

This page was reviewed under our medical and editorial policy by Vijay Trisal, M.D., surgical oncologist and chief clinical officer for the City of Hope^® system.

A biopsy is any type of procedure that removes a sample of tissue from the body so that it may be examined in a lab for signs of disease. Fine needle aspiration (FNA) is a type of biopsy that uses a very thin needle to collect a sample of cells or fluid from the site of a suspected tumor so that it may be checked for cancer.

What Is Fine Needle Aspiration?

FNA biopsy uses a very thin needle to take fluid or cell samples from a patient’s body. This sample is then reviewed under a microscope in a lab. FNA biopsy may be used to diagnose cancer or to help doctors gather more information about an existing cancer diagnosis. FNA uses a very thin needle that measures around half a millimeter across, or about the size of the tip of a sharpened pencil.

Fine Needle Aspiration Versus Core Needle Biopsy

FNA biopsy and core needle biopsy are two types of biopsy that may be used to remove a tissue sample from a patient’s body. The main difference between two procedures is in the size of the sample that is collected, as detailed below.

FNA biopsy: This type of biopsy uses a very thin needle and is a less invasive procedure than core needle biopsy. However, because FNA collects a smaller sample of cells, it may be slightly less accurate at diagnosing cancer or other conditions.

Core needle biopsy: This type of biopsy uses a slightly larger needle and collects a larger tissue sample. Core needle biopsy may provide a more accurate diagnosis than FNA.

Which type of biopsy doctors recommend depends on factors such as the location of the biopsy site, what type of cancer or tumor is suspected and a patient’s overall health.

Common Sites for an FNA

FNA biopsy is most often used to screen for or diagnose diseases such as:

• Breast cancer
• Cancer in the lymph nodes
• Skin cancer
• Thyroid cancer

Doctors may also use imaging technologies such as ultrasound or computed tomography to guide an FNA biopsy of harder-to-reach areas in the digestive system, the esophagus or other parts of the body.

The Procedure

An FNA biopsy is usually a very quick procedure and is performed in a doctor’s office or clinic, often by a doctor who specializes in the area of the body that is being biopsied. During an FNA. For the procedure:

• A patient sits or lies down, depending on where the FNA biopsy is being performed.
• Anesthetic is usually only needed for biopsies of a particularly sensitive area of the body.
• Doctors insert a very thin needle into the site of the biopsy and used this needle to withdraw a sample of fluid or cells.
• This process is often repeated several times in the same general area, allowing doctors to collect a sufficient sample for analysis.
• The needle is removed and the wound is covered with a bandage.

Recovery from an FNA biopsy is quick and easy, because the needle used to collect the tissue sample only requires a very small incision into the skin. Some patients may experience mild discomfort or bleeding at the site of the biopsy, but this usually resolves very quickly.

Results of a Fine Needle Aspiration

After a sample is collected using FNA biopsy, that sample is sent to a lab, where it is examined under a microscope by a doctor who specializes in reviewing tissue samples. The doctor looks for signs of changes on a cellular level that may be related to cancer, infection or disease. It may take several days up to a week to receive the results of an FNA biopsy.