- What is bone marrow?
- What is a bone marrow procedure (aspiration and/or biopsy)?
- What types of doctors perform bone marrow aspirates and/or bone marrow biopsies?
- Why are bone marrow biopsies or aspirations done?
- What bone is used to sample the bone marrow?
- How is a bone marrow aspiration and/or biopsy performed?
- What is done with the bone marrow sample?
- What diseases are diagnosed by bone marrow examination?
- What are the risks or complications of a bone marrow procedure?
What is bone marrow?
The soft spongy tissue in the center of bones is the bone marrow. The bone marrow contains the different types of cells (stem cells) that give rise to the red cells, white cells, and platelets found in our blood. The marrow may also contain abnormal cells, proteins, or inflammatory reactions that are not normally present, such as cancer cells in some individuals. Since the production of red cells requires iron, the marrow is one of the places in the body that normally stores a supply of iron. When we are younger, our bone marrow contains very little fat. As we age, the percentage of fat in our marrow increases.
What is a bone marrow procedure (aspiration and/or biopsy)?
A bone marrow procedure (commonly referred to as a bone marrow or bone marrow aspiration with or without biopsy or trephination) is a technique used to obtain a sample of the blood-forming portion (marrow) of the inner core of bone for examination in the laboratory or for transplantation. A bone marrow aspiration consists of inserting a special needle into a bone and withdrawing the marrow by suction. A bone marrow biopsy takes out a larger piece of the bone marrow by coring out a sample of the marrow.
What types of doctors perform bone marrow aspirates and/or bone marrow biopsies?
In general, internists, hematologists, oncologists, and transplant specialists are the doctors that usually perform bone marrow aspirates and/or biopsies.
Why are bone marrow biopsies or aspirations done?
Most bone marrow aspirations are performed to diagnose various conditions that affect the different types of blood cells. Abnormal blood counts can lead a doctor to suspect that there may be a problem in the bone marrow. Another frequent purpose of a bone marrow is to diagnose certain cancers or to determine the extent of a cancer (cancer staging) that is present within the bone marrow. Bone marrow procedures can also detect uncommon conditions, both cancerous and noncancerous, including abnormal proteins (such as in amyloidosis), inflammation (such as in sarcoidosis), and infection (such as in tuberculosis). This procedure can also be used to obtain marrow cells for transplantation.
Bone marrow biopsies remove a core of bone to allow physicians to evaluate the structure of the tissue with a microscope. These reveal both the bone and any associated cells, protein deposits, or inflammatory processes. A bone marrow aspirate is primarily a liquid sample that reveals the mixed cell population of cells within the marrow. An aspirate does not show the relationship of the cells to each other or to the bone, or the cells' precise location in relation to the bone. The procedures may be performed together, with an aspirate obtained prior to a biopsy.
What bone is used to sample the bone marrow?
The most frequent site for obtaining bone marrow is the pelvic bone, known as the ilium (posterior iliac crest). A portion of this bone is readily accessible in most people from the lower back and is usually marked by shallow dimples on either side of the spine. Other sites include the front of the pelvic bone near the groin and the sternum at the front of the chest. However, the sternum is sampled only for aspiration and done in individuals older than 12 years of age. This site is considered to be "a last resort" because the sternum is thin and there is risk of penetrating the underlying soft tissues. The tibia (shinbone) is sampled only in infants younger than 1 year of age; it is not sampled in adults because it may not yield a sufficient sample of bone marrow cells.