Fine needle aspiration (FNA)

A fine needle aspiration (FNA) is a type of biopsy. FNA is an alternative to more invasive biopsy methods, such as core biopsy or excisional biopsy. During an FNA, a very thin needle is used to collect a sample of cells, tissue or fluid from an abnormal area or lump. The sample is then examined under a microscope.

FNA is often used to check whether suspicious lumps are cancerous, including in the neck, breast, lymph nodes or in deeper organs such as the liver and pancreas. FNA is also called fine needle aspiration biopsy or fine needle biopsy.

Doctors may use an FNA to:

• check an area in the body such as the thyroid, breast, liver, lung, skin or lymph nodes for cancer, usually done when a lump is found through a physical exam or imaging tests. An FNA might find conditions other than cancer, including a benign tumour, infection or inflammatory disorder.
• determine the type of cancer
• check if cancer has spread to the lymph nodes or another organ
• drain fluid from a cyst to help relieve symptoms such as tenderness or pain
• treat an abscess
• determine genetic or molecular markers that may help decide treatment for advanced cancer

You may have an FNA in a doctor’s office or as an outpatient in a hospital. It will be done by a specialist such as a radiologist, surgeon, endocrinologist, gastroenterologist or pathologist. A FNA near the surface of the body does not usually take very long. Your healthcare team will let you know what to expect during the procedure, but you don't need to prepare for it. You usually won't need a local anesthetic for the test unless it is in a sensitive area (such as the breast or prostate).

Sometimes doctors use an imaging test, such as an ultrasound or CT scan, to guide the needle into the specific area they want to take a sample from using an FNA. These tests are commonly done when the area is deep in the body, very small or can't be felt. An FNA of organs that aren't near the surface of the body may be done during an endoscopic ultrasound (EUS). An EUS uses a small ultrasound probe on the end of the endoscope to make images of parts of the body. If the doctor is doing an FNA in a deeper part of the body, you will need to prepare for the EUS or another procedure that may be done with a general anesthetic.

You will need to either sit up or lie down for the FNA. The healthcare team will clean the area where the needle will go in.

During an FNA, the doctor inserts a very thin needle through the skin and into the area being examined. The needle is usually attached to a syringe. The doctor slowly draws, or aspirates, cells, tissue or fluid through the needle and into the syringe. You may feel some pressure or discomfort during the FNA, but it’s not usually painful.

The doctor usually does more than one FNA to collect multiple samples from different areas. Multiple FNAs are often needed to collect enough material to make a diagnosis. The doctor will use new needles and syringes in each FNA.

After the doctor removes the needle, a bandage is put over the area where the needle was inserted. The cells, tissue or fluid collected (called the biopsy sample) is sent to a pathology lab to be examined. The doctor may test the sample on site to make sure that there is enough material to avoid having to do the biopsy again.

An FNA usually only causes mild discomfort or soreness. Other side effects of an FNA may include:

• bruising or bleeding
• swelling

Less common but more severe side effects include:

• infection
• injury to tissue or organs near the area that was tested

A pathologist (a specialized doctor that helps determine the diagnosis, prognosis and treatment of a disease by looking at the cells and tissue under a microscope) will send a report to your doctor with the results of the FNA. The doctor will usually receive the report within a few days. The report may include details about the cell type and whether they are normal, abnormal or cancer cells. If you are having an FNA to treat a non-cancerous cyst, a pathology report may not be done. An FNA report may show the following in the sample:

• the cells are normal
• the lump or area tested is non-cancerous (such as a breast cyst)
• there is an infection
• there are precancerous or abnormal cells
• there are cancer cells

Sometimes you will need to have another FNA or other type of biopsy (such as a core biopsy) to confirm the diagnosis or if the FNA did not collect enough tissue or fluid to make a diagnosis. Your doctor will talk to you about the results and decide if more tests, procedures, follow-up care or treatment is needed.

To prepare a child for an FNA, you can explain what will happen during the test, such as what the child will see, feel and hear. Preparing children before a test or procedure can lower their anxiety, make them more cooperative and help develop their coping skills.

The preparation for an FNA depends on the age and experience of the child. Your child’s doctor or healthcare team will tell you if your child needs to stop eating and drinking before the FNA. Your child may be given a local or general anesthetic.

Find out more about helping children cope with tests and treatment.