Bone marrow aspiration is a procedure that involves taking a sample of the liquid part of the soft tissue inside your bones.

Bone marrow is the spongy tissue found inside bones. It contains cells that produce white blood cells (WBCs), red blood cells (RBCs), and platelets inside larger bones, such as the:

  • breastbone
  • hips
  • ribs

WBCs help fight infection. RBCs carry oxygen and nutrients. Platelets enable your blood to clot.

A complete blood count (CBC) shows the number of red blood cells, white blood cells, and platelets, which can be abnormally high or low. If this happens, your doctor may want to examine your bone marrow to find the cause.

Bone marrow aspiration is often performed with a bone marrow biopsy. However, a different needle is used in a bone marrow biopsy to remove solid tissue from your bone marrow.

Some conditions are associated with unhealthy bone marrow. If preliminary blood tests show abnormal levels of white or red blood cells or platelets, your doctor may order a bone marrow aspiration.

The test helps identify the particular disease, and it monitors the progression or treatment of a disease. Conditions and diseases related to bone marrow problems include:

Bone marrow aspiration can be an important test if you’re having cancer treatment. It can help determine if the cancer has spread to the bones.

While bone marrow exams are safe, all medical procedures carry some type of risk. Possible complications include:

The risks are rare and most often associated with conditions that cause a weakened immune system or low platelet count. A weakened immune system can make you more prone to infection. A low platelet count increases your risk of excessive bleeding.

You should let your doctor know about any medications you may be taking, including over-the-counter (OTC) medicines or nutritional supplements. You should also let them know about any allergies you have.

Your doctor may ask you to stop taking certain medications before the procedure. But you shouldn’t stop taking any medications unless your doctor tells you to.

Tell your doctor if you’re nervous about the procedure. They may give you a mild sedative to help you relax.

Follow any additional instructions your doctor gives you before the procedure.

You’ll be asked to change into a hospital gown and lie down on your side or abdomen. Your body will be covered with a cloth so only the area being examined is visible.

Your doctor will check your temperature, heart rate, and blood pressure before the bone marrow aspiration.

Before the procedure, you’ll be given local anesthesia to numb the area where the aspiration will be performed. This is typically at the top ridge of the rear of the hipbone. Sometimes it may be taken from the chest bone. You may also be given a combination of IV medications by vein to help with sedation and pain.

Your doctor will insert a hollow needle through your skin and into the bone. The center portion of the needle is removed and a syringe is attached to draw fluid out of the marrow. There may be a dull ache.

Right after the procedure, your doctor will bandage the site, and you’ll rest in another room before going home.

You may feel some slight pain for about a week after the procedure. You can typically manage it with OTC pain relievers. You’ll also have to take care of the needle insertion site. You should keep the wound dry for 24 hours after the procedure and follow your doctor’s instruction for wound care.

While you’re caring for your wound, your bone marrow sample will be sent to a laboratory for testing. Your doctor will review test results with you during a follow-up appointment.