Emla is usually applied to your back an hour before the test. This is a cream to numb the skin. For the test, you will lay on your stomach. A rolled-up towel will placed under your stomach, and the doctor will clean your back with brown soap (betadine) to keep the germs away. A small needle is used to give you more numbing medicine in your back. During this whole time, your parent or guardian can be in the room, and a Child Life Specialist will help you through the procedure as well.

If you like, the doctor will tell you when he/she is ready to perform the bone marrow test. A needle will be inserted, and most kids say they feel pressure and pushing and some feel it in their legs. A big bandage, called a pressure dressing, is applied. The total test doesn't take very long.