Why do I need a bone marrow biopsy?

Myeloma starts in the bone marrow, so blood tests alone cannot give the full picture. Finding 10% or more abnormal plasma cells confirms multiple myeloma, and 60% or more means highly active disease. The sample also supplies cells for DNA testing that guides the right medicines.

What happens during the procedure?

Doctors usually take both a liquid aspiration and a tiny solid core from the back of the hip bone. The area is numbed with local anesthetic, and you may also receive medicine to partly or fully sedate you. You will likely feel pressure and brief, temporary pain as the samples are drawn.

What is FISH testing?

FISH uses glowing dyes to look at the chromosomes inside your myeloma cells. Changes such as del(17p), 1q gain, t(4;14), or t(14;16) can mean the myeloma is high-risk and more aggressive. That information lets your team tailor a stronger, more precise plan.

When is a repeat biopsy needed?

You will not have a biopsy at every visit, only at major milestones. After treatment, a repeat sample is needed to confirm a complete response and to look for minimal residual disease, even 1 hidden myeloma cell in 100,000 normal cells. At suspected relapse, another biopsy checks whether the cancer's genetics have changed.

Some discomfort is expected, but the site is numbed and sedation can be offered. Most people feel pressure plus brief pain when the samples are taken. Understanding the steps and purpose of the test can make it easier to go through.

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First-Line TreatmentRelapse Management

Understanding Bone Marrow Biopsies

Name: Understanding Bone Marrow Biopsies | CMDN
Creator: CMDN Editorial Team
Published: 2026-07-30

The Window into Your Marrow

Medical Disclaimer: The following content is compiled based on the latest authoritative guidelines at home and abroad. It is for reference only for patients and their families and cannot replace the professional medical advice of the attending physician. Please be sure to follow the doctor's advice for the treatment plan.

Core Conclusion

A standardized bone marrow biopsy collecting a 1 to 2 cm core biopsy provides definitive histologic proof of plasma cell infiltration (≥10% threshold) and supplies samples for FISH cytogenetic testing in 100% of evaluations.

Detailed Points

(1) Why this procedure is necessary: Myeloma is a cancer that starts in the bone marrow, so standard blood tests alone cannot give your doctor the full picture. Your doctor needs to look directly at the tissue to check your plasma cell percentage. Finding >= 10%$ abnormal (clonal) plasma cells in the marrow confirms a diagnosis of multiple myeloma, while a level of >= 60%$ indicates highly active disease. Furthermore, the biopsy provides the actual physical cells needed to test the DNA of your cancer, which is crucial for choosing the right medications for you.
(2) What to expect during the procedure: The procedure involves two parts usually done at the same time: an aspiration (where a needle is used to pull out a small amount of liquid bone marrow) and a biopsy (where a slightly larger, hollow needle is used to remove a tiny, solid core of the bone tissue itself).
- The physical experience: The samples are almost always taken from the back of your pelvic (hip) bone, as it contains plenty of marrow and is close to the surface. To keep you comfortable, your doctor will use a local anesthetic to numb the area, and you may also be offered medicine to partially or completely sedate you. You will likely feel a sensation of pressure and some brief, temporary pain as the samples are drawn.
(3) Cytogenetic testing (FISH) for risk status: Once your marrow is collected, scientists perform a highly specialized test called FISH (Fluorescence In Situ Hybridization) on the myeloma cells. They use special glowing dyes to look at the chromosomes (the "instruction manuals") inside your cells to see if they are broken, missing, or rearranged. Detecting specific structural changes—such as missing pieces like del(17p), extra copies like 1q gain, or swapped pieces like t(4;14) or t(14;16)—tells your doctor if your myeloma is "high-risk" and might behave more aggressively. This allows your team to tailor a stronger, more precise treatment plan just for you.
(4) When a repeat biopsy is typically required: You will not need a bone marrow biopsy at every visit, but it is repeated at major milestones in your journey.
- Confirming Remission & MRD: If your blood tests look completely normal after treatment (like a stem cell transplant), a repeat biopsy is obligatory to officially confirm a Complete Response (CR). It is also used to check for Minimal Residual Disease (MRD)—an ultra-sensitive test using next-generation sequencing or flow cytometry that searches for even 1 single hidden myeloma cell out of 100,000 normal cells.
- At Relapse: If your doctor suspects your myeloma has returned, a repeat biopsy is often performed to see if the genetics of the cancer have changed (mutated) over time, which helps guide your next phase of treatment.

The above content is sourced from the following references

Patient Handbook
MMRF Learn Your Labs
NCCN Guidelines for Patients® Multiple Myeloma
EHA–EMN Evidence-Based Guidelines for diagnosis, treatment and follow-up of patients with multiple myeloma

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FAQs

Why do I need a bone marrow biopsy?: Myeloma starts in the bone marrow, so blood tests alone cannot give the full picture. Finding 10% or more abnormal plasma cells confirms multiple myeloma, and 60% or more means highly active disease. The sample also supplies cells for DNA testing that guides the right medicines.
What happens during the procedure?: Doctors usually take both a liquid aspiration and a tiny solid core from the back of the hip bone. The area is numbed with local anesthetic, and you may also receive medicine to partly or fully sedate you. You will likely feel pressure and brief, temporary pain as the samples are drawn.
What is FISH testing?: FISH uses glowing dyes to look at the chromosomes inside your myeloma cells. Changes such as del(17p), 1q gain, t(4;14), or t(14;16) can mean the myeloma is high-risk and more aggressive. That information lets your team tailor a stronger, more precise plan.
When is a repeat biopsy needed?: You will not have a biopsy at every visit, only at major milestones. After treatment, a repeat sample is needed to confirm a complete response and to look for minimal residual disease, even 1 hidden myeloma cell in 100,000 normal cells. At suspected relapse, another biopsy checks whether the cancer's genetics have changed.
Does a biopsy hurt?: Some discomfort is expected, but the site is numbed and sedation can be offered. Most people feel pressure plus brief pain when the samples are taken. Understanding the steps and purpose of the test can make it easier to go through.

References used for this guide

Sincere thanks to the following authoritative institutions
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for myeloma patients globally

Disclaimer: All disease knowledge, guideline interpretations, and treatment processes provided on this site are for learning and reference only, and do not constitute any medical advice or professional diagnosis. The condition of each patient is unique. For specific treatment plans and medication decisions, please be sure to follow the guidance of your attending physician or professional medical team.

This article is reviewed and published by the CMDN Editorial Team

Last updated: 2026-07-30

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