Fine-needle aspiration

When a physician or nurse inserts a needle into the body to remove cells or fluid, this is called an aspiration. An aspiration is performed with a thin hollow needle.

After the aspiration, the contents of the syringe (aspirate) are sent to the laboratory. A laboratory technician examines them under a microscope for abnormalities or disease.

Types of aspiration

There are several types of aspiration. They all have one thing in common: whatever is removed from the body, it is removed with a thin hollow needle. Examples include:

• Drawing blood.
• Removing fluid from a swollen joint.
• Amniocentesis during pregnancy.
• Aspirating cells from an area of inflammation.

Who performs an aspiration?

A nurse or physician performs the aspiration. If the needle must be inserted in a difficult-to-reach or dangerous location, such as the neck, it is often performed in the hospital's radiology department. The procedure may be guided by ultrasound or performed during a CT scan, allowing the needle position to be monitored accurately.

How do you prepare for an aspiration?

There is not much you can do to prepare, but keep the following in mind:

• Temporarily stop taking blood thinners, as they increase the risk of bleeding. Discuss this with your physician.
• Do not eat or drink anything for 2 hours beforehand.
• Ask someone to accompany you to the hospital if necessary.

During the aspiration

An aspiration is not a major procedure and is usually performed without anesthesia, unless several needle insertions are needed in the same area.
After disinfecting the skin, the physician inserts the needle into the correct location. The needle may be moved slightly up and down to collect enough cells. Once sufficient material has been collected, the needle is removed. The examination then ends. It usually takes about 20 to 60 minutes.

After the aspiration

You can usually go home immediately afterward. An aspiration generally causes no serious side effects, although the site may remain tender for a few days or develop a bruise. This is not a cause for concern.

Results take about a week. During this time, the aspirate is examined. The treating physician or primary care physician will provide the laboratory results.

Difference between aspiration and biopsy

Aspiration and needle biopsy are sometimes confused. The main difference is that a biopsy removes pieces of tissue rather than only fluid or cells. A thicker hollow needle is used.

Removing tissue for examination during surgery is also considered a biopsy. In that case, a knife or forceps is used instead of a needle. A biopsy specimen usually provides more information about a disease or abnormality than an aspirate.