Fine Needle Aspiration

This is a simple test, which is done routinely in the investigations of patients with lumps in the thyroid gland. Having a lump in the thyroid is very common (about 5% of all women have a lump in their thyroid) and the vast majority of these lumps (95% of them) are benign. To find out more about the lump it is necessary to try and get a sample of the cells in the lump, which we do by fine needle aspiration.  Some lumps are very obvious and there is no problem finding the site to aspirate.  Nevertheless there are some lumps which are found deep within the thyroid and then ultrasound scanning is required at the same time as aspiration to ensure that the lump itself is accurately aspirated.

Fine Needle Aspiration is very similar to getting a blood sample. You are placed lying down with your neck extended. The skin overlying the lump is cleaned with a small swab and then a small needle is passed into the lump and some of the cells are sucked into a syringe, which are later looked at under a microscope. After the needle is removed, gentle pressure with a cotton wool swab is applied for a few minutes, to try and stop any bruising occurring. We usually do two passes with the needle, in order to increase the chances of getting cells into the syringe. Occasionally, only blood is sucked out by the syringe, rather than any cells, because the thyroid is a very vascular gland. In these cases the test is repeated to try and get some cells.

This test gives the doctors a very good idea as to what the lump is made of and whether the lump needs an operation or not. If the test shows abnormal cells, then the doctor will recommend an operation to remove the lump. If the cells are normal looking then the lump can be left alone and the test is normally repeated in about 6 months, just to make sure that there is no abnormality in the cells.

Ó NHS Tayside; 2006; version 1.0

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