In a bone marrow biopsy, a doctor uses a needle to remove and examine a small amount of bone marrow, the spongy tissue inside some of the body’s larger bones.
Bone marrow, which generates all the different kinds of cells within the blood, has the consistency of a gel in a fine mesh of bone. A bone marrow biopsy involves removing a semi-solid “core” sample of marrow. In a related procedure, known as a bone marrow aspiration, bone marrow is drawn into a syringe as a liquid that looks like blood but contains white particles known as bone “spicules.” It’s common for both procedures, known as bone marrow exams, to be performed at the same time.
Bone marrow exams are used to diagnose a variety of conditions, including anemia; blood-related cancers such leukemia, lymphoma, multiple myeloma, myelodysplatic diseases, and Waldenström’s Macroglobulinemia; certain non-cancerous blood disorders; infections that start in the bone marrow; and cancers that have spread to the bone marrow from elsewhere in the body.
A bone marrow biopsy and/or aspiration are often performed after a blood test shows certain abnormalities – an overabundance or shortage of specific kinds of blood cells, or the presence of abnormal cells. A bone marrow exam provides more detailed information about the source of the problem. Such exams can help doctors diagnose diseases of the bone marrow or blood cells, and determine a course of treatment and monitor its effectiveness.
The liquid material collected in a bone marrow aspirate can be immediately analyzed using a variety of tests. A biopsy, by contrast, provides additional information about the “architecture” of the bone marrow – the relative locations of the various types of cells in the marrow, which can greatly aid in making diagnoses. However, since the bone structure in a biopsy needs to be dissolved before an analysis can be performed, the results from biopsies take several days to be completed.
Bone marrow biopsies and aspirations are generally safe and are often performed on an outpatient basis. The exams take only about 10 minutes, although extra time is needed for preparation and post-procedure care. The total time for the procedure is about 30 minutes.
Prior to the procedure, patients have their blood pressure and heart rate checked and are given some form of anesthesia – usually a local anesthetic to numb the area where the procedure will be performed. The area is draped in a cloth. In adults, marrow is usually extracted from the crest of the back of the hipbone. Bone marrow aspirations, but not biopsies, are sometimes performed on the breastbone or, in children under 12, the lower leg bone.
To perform a bone marrow aspiration, which usually precedes a bone marrow biopsy, the doctor makes a small incision and inserts a hollow needle into the bone marrow. With a syringe attached to the needle, the doctor withdraws a sample of the fluid portion of the marrow. For a bone marrow biopsy, the procedure is the same but involves a larger needle designed to collect the harder portion of the marrow.
The tissue samples are then examined by a pathologist, who evaluates the number and appearance of various cell types, and often performs genetic and molecular analyses to detect other disease-related abnormalities.