Reviewed May 1, 2026

Definition

A bone marrow biopsy is the removal of marrow from inside one of your bones. Bone marrow is the soft tissue inside bones that helps form blood cells. It is found in the hollow part of most bones.

Bone marrow biopsy is not the same as bone marrow aspiration. An aspiration removes a small amount of marrow in liquid form for examination.

Alternative Names

Biopsy - bone marrow

How the Test is Performed

A bone marrow biopsy may be done in your health care provider's office or in a hospital. The sample is usually taken from the pelvic bone. Sometimes, another bone site is used.

Marrow is removed in the following steps:

  • If needed, you are given medicine to help you relax.
  • Your provider cleans the skin and injects numbing medicine into the area and surface of the bone.
  • A biopsy needle is inserted into the bone. The center of the needle is removed and the hollowed needle is moved deeper into the bone. This captures a tiny sample, or core, of bone marrow within the needle.
  • The sample and needle are removed.
  • Pressure and then a bandage are applied to the skin.

A bone marrow aspiration may also be done, usually before the biopsy is taken. After the skin is numbed, the needle is inserted into the bone, and a syringe is used to withdraw the liquid bone marrow. If this is done, the needle will be removed and repositioned. Or, another needle may be used for the biopsy.

How to Prepare for the Test

Tell your provider:

  • If you are allergic to any medicines
  • If you are pregnant
  • If you have bleeding problems
  • What medicines you are taking

How the Test will Feel

You will feel a sharp sting when the numbing medicine is injected. The biopsy needle may also cause a brief, usually dull, pain. Since the inside of the bone cannot be numbed, this test may cause some discomfort.

If a bone marrow aspiration is also done, you will feel a brief, sharp pain as the bone marrow liquid is removed.

Why the Test is Performed

Your provider may order this test if you have abnormal types or numbers of red or white blood cells or platelets on a complete blood count (CBC).

This test is used to diagnose:

  • Anemia (some types)
  • Certain infections
  • Leukemia
  • Other blood cancers and disorders

It may also be used to help determine if a cancer has spread or responded to treatment.

Normal Results

A normal result means the bone marrow contains the proper number and types of blood-forming (hematopoietic) cells, fat cells, and connective tissues.

What Abnormal Results Mean

The results may detect the cause of anemia (too few red blood cells), abnormal white blood cells, or thrombocytopenia (too few platelets).

Abnormal results may be due to bone marrow cancers, including:

  • Acute lymphocytic leukemia (ALL)
  • Acute myelogenous leukemia (AML)
  • Chronic lymphocytic leukemia (CLL)
  • Chronic myelogenous leukemia (CML)

Abnormal results may also be due to other causes, such as:

  • A nerve tissue tumor called neuroblastoma
  • A white blood cell cancer called hairy cell leukemia
  • Abnormal protein buildup in tissues and organs (amyloidosis)
  • Bone marrow doesn't make enough blood cells (aplastic anemia)
  • Bacterial or fungal infections that have spread throughout the body such as tuberculosis or coccidioidomycosis
  • Cancer of the lymph tissue (Hodgkin or non-Hodgkin lymphoma)
  • A bleeding disorder called idiopathic thrombocytopenic purpura (ITP)
  • Blood cancer called multiple myeloma
  • Disease in which the bone marrow is replaced by scar tissue (myelofibrosis)
  • Disease in which the bone marrow produces too many red blood cells (polycythemia) or platelets (thrombocytosis)
  • Disease in which not enough healthy blood cells are made (myelodysplastic syndrome; MDS)
  • White blood cell cancer called Waldenström macroglobulinemia

Risks

There may be some bleeding at the puncture site. More serious risks, such as serious bleeding or infection, are very rare.

References

Choby BA. Bone marrow aspiration and biopsy. In: Fowler GC, ed. Pfenninger and Fowler's Procedures for Primary Care. 4th ed. Philadelphia, PA: Elsevier; 2020:chap 220.

DeZern AE, Brodsky RA. Aplastic anemia and related bone marrow failure states. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 151.

Vajpayee N, Graham SS, Bem S. Basic examination of blood and bone marrow. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 31.

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Information developed by A.D.A.M., Inc. regarding tests and test results may not directly correspond with information provided by UCSF Health. Please discuss with your doctor any questions or concerns you may have.