Originally published by Harvard Health.
What is the test?
Doctors can diagnose many problems that cause anemia, some infections, and some kinds of leukemia or lymphoma cancers by examining a sample of your bone marrow. Bone marrow is the tissue where blood cells are made. A bone marrow biopsy is the procedure to collect such a sample. It is done using a needle inserted through the outside surface of a bone and into the middle of the bone, where the marrow is.
How do I prepare for the test?
You will need to sign a consent form giving your doctor permission to perform this test. Because you will probably receive some pain medicines or anti-anxiety medications that can make you drowsy, you will need to arrange a ride home.
Tell your doctor if you have ever had an allergic reaction to lidocaine or the numbing medicine used at the dentist’s office. Also talk with your doctor before the test if you are taking insulin, or if you take aspirin, nonsteroidal anti-inflammatory drugs, or other medicines that affect blood clotting. It may be necessary to stop or adjust the dose of these medicines before your test.
Sometimes the doctor will not want you to eat for several hours prior to the test. Check with your doctor.
What happens when the test is performed?
Most patients have this test done by a hematologist (a blood specialist). You wear a hospital gown during the procedure. A sedative may be injected at this time. (If you are prescribed a sedative in pill form, you will be instructed to take it ahead of time.)
Most patients have bone marrow sampled from the pelvis. You lie on your stomach and the doctor feels the bones at the top of your buttock. An area on your buttock is cleaned with soap. A local anesthetic is injected to numb the skin and the tissue underneath the skin in the sampling area. This causes a brief stinging sensation.
A small cut is made in the skin to allow the biopsy needle to be placed through the skin. This needle is about half as wide as a pencil and has a handle on one end that your doctor holds while he or she moves it through your bone. The biopsy needle is moved through the bone with a twisting motion, as a corkscrew would be moved through a cork.
When the needle has passed through the top layer of bone, your doctor uses a syringe to pull a liquid sample of your bone marrow cells through the needle. For most patients, the suction used in this liquid collection causes a pain in the buttock for a few seconds.
After taking the liquid sample, the doctor carefully moves the needle a little bit further into the bone marrow to collect a second sample of marrow called a core biopsy. This core biopsy is a small solid piece of bone marrow. The sample contains cells and also the fat and bone fibers that hold them together.
After the needle is pulled out, this solid sample can be pushed out of the needle with a wire so that it can be examined under a microscope. Pressure is applied to your buttock at the biopsy location for a few minutes. A bandage is placed on your buttock.
What risks are there from the test?
Risks are minimal. Having a sample taken is not harmful for your bone or bone marrow. Injury of nearby tissue from the biopsy is very uncommon. You might have some buttock soreness for a few days, and you may have some bruising at the biopsy site. A few individuals have an allergy or a side effect from the pain medicine or anti-anxiety medicine.
Must I do anything special after the test is over?
You will feel sleepy from the medicines used to reduce pain and anxiety. Once these medicines have worn off (a few hours after the test), you can return to normal activities, but you should not drive or drink alcohol for the rest of the day.
How long is it before the result of the test is known?
The samples taken need to be treated in the laboratory and prepared on slides that can be seen under the microscope. Some parts of your bone marrow biopsy report may be available within a day, but some tests require special stains or tests that can take longer, in some cases a week or longer.