What is a Fine Needle Biopsy?

A fine needle biopsy is a diagnostic medical procedure carried out to collect a sample of cells or fluid for testing. This is a common nonsurgical diagnostic test carried out to diagnose and assess cancers and other types of illness. Fine needle biopsy also can be referred to as fine needle aspiration, fluid aspiration and core needle biopsy, depending on the type of tissue sample that is obtained.

Disease diagnosis is the most well-known reason for undergoing a fine needle biopsy. For example, this procedure is carried out when someone has an unidentified lump or mass that might be malignant. A sample taken via a needle biopsy can be tested in a laboratory for the presence of cancer cells, proteins produced by cancer cells and many other indicators of disease.

Although this is known to most people as a diagnostic procedure, fine needle biopsy also can be used as a means of measuring an individual’s response to treatment. In the case of a person who has cancer, for example, a biopsy might be taken after surgery or another cancer treatment. In conjunction with other test results, the biopsy results are used as a means of determining whether the treatment has been successful.

Fine needle biopsy is used to diagnose and assess what are known as superficial lumps or masses. This means that the lump or mass is located just below the skin, rather than within one of the body’s cavities. In contrast, an excisional or open biopsy is a surgical procedure in which an incision is made under general anesthetic to allow a surgeon access to tissues within a body cavity.

To prepare for the biopsy, a patient must stop using all blood-thinning medications for one week before the procedure. This includes prescription medications as well as over-the-counter drugs with blood-thinning properties. In addition, patients must not eat for several hours prior to the biopsy.

Before the biopsy begins, the patient’s vital signs, including temperature, blood pressure and pulse, are taken. If a patient is very anxious and unable to relax, he or she might be given an oral sedative as an aid to relaxation. After all preparation is complete, the biopsy location is sterilized and then anesthetized with a local anesthetic. If necessary, the location of the mass might be determined via X-ray before the biopsy itself.

After the location has been pinpointed, a very fine needle is inserted into the mass to withdraw a sample of cells and fluid. Often, several samples are taken from different locations within the mass. This is important because if just one sample is taken, the accuracy of the test is reduced, possibly leading to a false negative result or an indeterminate diagnosis.

Minor side effects of fine needle biopsy such as bruising and tenderness at the site of needle insertion are fairly common. Depending on the site of biopsy, a small amount of blood in mucus or urine also is normal. If symptoms such as chills, fever, severe pain at the biopsy site, difficulty breathing, dizziness or chest pain are experienced, medical attention should be sought immediately.