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Bone Marrow Aspiration and Biopsy

What is bone marrow?

Bone marrow is a soft, spongy material that is in the center of most of the body’s bones. Bone marrow works like a blood cell factory. It makes blood-forming (hematopoietic) cells, the parents of all other blood cells. They mature into cells that eventually become:

  • Red blood cells (which carry oxygen)
  • Platelets (which help the blood clot)
  • White blood cells (which fight infection)

What is bone marrow aspiration and biopsy?

Bone marrow aspiration (sometimes called bone marrow aspirate) and biopsy are tests performed to examine a patient’s bone marrow.

What is bone marrow? Bone marrow is a soft, spongy material in the center of most of the body’s bones that works like a blood cell factory.

Bone marrow is a soft, spongy material in the center of most of the body’s bones that works like a blood cell factory.

Bone marrow aspirations and biopsies may help:

  • See if the bone marrow is producing enough of certain blood cells
  • Diagnose blood cancers, such as childhood leukemia and lymphoma
  • Determine if cancers have spread from other parts of the body to the bone marrow
  • See if bone marrow is responding to treatments
  • Diagnose bone marrow infections

How bone marrow tests are performed

Many patients will have an aspiration and biopsy at the same time. Sometimes patients only have a bone marrow aspiration.

Bone marrow has a liquid portion and a more solid portion. The liquid portion is removed during an aspiration. The solid portion is removed during a biopsy.

Learn more about blood by visiting the Basics of Blood website.

Preparing for bone marrow tests

Your child will like receive medicine to help them sleep during the procedure. 

If your child receives a medicine to help them sleep, they must follow rules for eating and drinking before having the test. If your child does not follow the rules about food and drink, the procedure will have to be rescheduled.

If your child does not have a central line or port, they will receive the medicine through an IV.

Bone marrow aspiration

A member of your child’s care team typically performs a bone marrow aspiration. A small sample of bone marrow is removed using a thin, hollow needle attached to a syringe.

  • Samples are usually taken from the hipbone.
  • Numbing medication, either a cream or an injection, may be applied at the procedure site.
  • Your child will usually lie on their side.
  • The person performing the procedure will feel your child’s lower back to find the right spot for the test.
  • The area will be cleaned with a germ-killing liquid. The liquid will feel cold. Then, the health care provider might place plastic towels over the back, leaving only a small area of skin showing.
  • The care team member will insert the needle, which will be attached at a syringe. Your child will feel some hard pushing if they are awake.
  • The care team member will pull some liquid marrow (which looks like blood) into a syringe. If awake, your child may feel some quick, sharp pain for an instant.
  • It is not unusual for the care team to attach more than one syringe if more samples are needed. Your child’s body will quickly replace the small amount of the fluid that has been taken out.
  • The care team member will take out the needle, clean the spot, and put on a bandage.
Patients usually lie on their side, and the sample is typically taken from the patient’s hipbone.

Patients usually lie on their side, and the sample is typically taken from the patient’s hipbone.

A small sample of bone marrow is removed using a thin, hollow needle attached to a syringe.

A small sample of bone marrow is removed using a thin, hollow needle attached to a syringe.

The patient will feel some hard pushing if he or she is awake.

The patient will feel some hard pushing if he or she is awake.

Bone marrow biopsy

  • If both an aspiration and biopsy are done, a separate needle will be used for each procedure.
  • For a biopsy, the care team will insert a larger needle into the same area to remove a small piece of bone tissue with enclosed marrow.
  • The biopsy is typically performed right before or after the aspiration.

The total time for both procedures is usually about 30 minutes.

After the procedure

A member of your child’s care team will update you about the procedure after it is completed.

You will receive the results from a member of your child’s care team later.

Key points

  • Bone marrow aspiration and biopsy allows your child’s care team to examine their bone marrow.
  • Your child may have both an aspiration and a biopsy, or just an aspiration.
  • Your child may be given medicines to help them sleep through the procedure. Follow the instructions from your child’s care team exactly.
  • The procedure takes about half an hour to complete.
  • Your child’s care team will explain the results to you.


Reviewed: October 2022