What Are Bone Marrow Tests?

Bone marrow tests are used to check whether your bone marrow is healthy. These tests also show whether your bone marrow is making normal amounts of blood cells.

Bone marrow is the sponge-like tissue inside the bones. It contains stem cells that develop into the three types of blood cells that the body needs:

• Red blood cells carry oxygen through the body.
• White blood cells fight infection.
• Platelets (PLATE-lets) stop bleeding.

Another type of stem cell, called an embryonic (em-bre-ON-ik) stem cell, can develop into any type of cell in the body. These cells aren't found in bone marrow.

Overview

Doctors use bone marrow tests to diagnose blood and bone marrow diseases and conditions, including:

• Conditions in which a person produces too few or too many of certain types of blood cells
• Problems with the structure of red blood cells
• Bone marrow disorders, such as myelofibrosis (MI-e-lo-fi-BRO-sis)
• Some cancers, such as leukemia (lu-KE-me-ah)

Bone marrow tests also help doctors determine how severe a cancer is and how much it has spread in the body. The tests also are used to diagnose fevers and infections.

The two bone marrow tests are aspiration (as-pi-RA-shun) and biopsy.

Bone marrow aspiration usually is done first. For this test, your doctor removes a small amount of fluid bone marrow through a needle. He or she may have some idea of what the problem is, and the sample gives him or her useful information about the cells in the marrow.

A bone marrow biopsy is a followup test. It's done when an aspiration doesn't give needed information. Or, it's done when the doctor wants to examine the bone marrow structure itself. For a bone marrow biopsy, your doctor removes a small amount of bone marrow tissue through a larger needle.

Outlook

Bleeding and infection are the two most common risks of bone marrow tests, but they're rare. The tests are fairly simple, and they're safe for most people.

In some cases, these tests aren't safe for people with certain bleeding disorders (like hemophilia). Your doctor can tell you whether a bone marrow test is safe for you.

September 2007