context: Fine needle aspiration is a type of biopsy procedure. In fine needle aspiration, a thin needle is inserted into an area of abnormal-appearing tissue or body fluid. As with other types of biopsies, the sample collected during fine needle aspiration can help make a diagnosis or rule out conditions such as cancer. Fine needle aspiration is generally considered a safe procedure. Complications are infrequent. A fine needle aspiration is most often done on swellings or lumps located just under the skin. A lump may be felt during a doctor's examination. Or it may be discovered on an imaging test such as: CT scan mammogram ultrasound Imaging tests may also discover abnormal spots deeper inside the body. Doctors may recommend fine needle aspiration for areas such as: cysts (fluid-filled lumps) nodules or masses (solid lumps) enlarged lymph nodes Without a biopsy, it's usually hard for a doctor to confirm what these abnormal areas contain. And you may not know if they are a threat to your health. The most common reason to get a fine needle aspiration is to test for cancer. Most fine needle aspirations are done on these areas: breast thyroid gland lymph nodes in the neck, groin, or armpit Those types of fine needle aspirations are performed through the skin. Using endoscopy, doctors can also reach areas deeper in the body. An endoscopy uses a flexible tube with a light and camera attached. During an endoscopy, a doctor can do a fine needle aspiration on certain abnormal spots in the chest or abdomen. There is no one standard preparation before fine needle aspiration. You may be asked to take these preparations: Changes in medicines. Several days before the test, stop taking aspirin or other blood thinners. These include clopidogrel ( Plavix), warfarin ( Coumadin or Jantoven), or one of the newer direct oral anticoagulants, such as apixaban ( Eliquis) and dabigatran ( Pradaxa). Changes in diet. Do not eat or drink anything for several hours before the procedure. If you will be getting sedating medication, be sure to bring someone with you to drive you home. Most fine needle aspirations are outpatient procedures. For people undergoing fine needle aspiration through the skin, here's what to expect: Your skin over the area of the procedure will be cleaned with antiseptic solution. It will then be covered with a sterile drape or towels. The area may be injected with a numbing medication under your skin. Ultrasound may be used during the procedure. This will help locate the right area for fine needle aspiration. A thin needle attached to a syringe will be inserted through the skin into the abnormal area. A vacuum inside the syringe causes body fluid or tissue to be suctioned (aspirated) into the needle and syringe. The fine needle aspiration itself is usually a short procedure (less than 10 minutes). The biopsy sample may be examined under a microscope right away. This will let your doctor: Verify that a good sample was obtained Make a rapid diagnosis Or, the biopsy sample may be sent to a lab for further testing. People undergoing fine needle aspiration during endoscopy will have additional preparation. Most will receive sedating medications. Endoscopic procedures usually take longer than fine needle aspirations through the skin (typically up to an hour). If sedating medication is used during fine needle aspiration, you may be groggy and unable to work afterward. At the biopsy site, you may have some: swelling soreness pain In most people, over-the-counter pain medicines are enough to decrease discomfort. Examples include the generic drug acetaminophen. It is also sold under these brand names: Actamin Panadol Tylenol Final results of testing after a fine needle aspiration can take up to a week or longer. Preliminary results may be available sooner. Serious complications after fine needle aspiration are rare. Minor bleeding under the skin at the biopsy site can occur. This can result in a tender, swollen area called a hematoma. Infection at the biopsy site is rare, because sterile techniques and equipment are used for all fine needle aspirations. The risk of complications from fine needle aspiration during endoscopy is slightly higher. But it is still quite low for most people.