1800 202 8726
Bone marrow biopsy

Aspiration vs Trephine: — Why Both Are Taken

In a bone marrow biopsy, two different samples are collected from the same site. The aspiration draws liquid; the trephine removes a solid core of bone. They are not the same test done twice — each answers questions the other cannot.

Medically reviewed by Dr. Bharati Devi Gorantla, Medical Oncologist, MBBS · MD · DM (Adyar, Chennai) · ECMO · MRCP SCE (UK) · Last reviewed September 2026

  • Two samples, one visit — Both are usually collected from the back of the hip bone in a single sitting under local anaesthetic.
  • Different information — Aspiration shows individual cells in detail. The trephine shows how those cells are arranged inside the bone.
  • Neither replaces the other — Patchy disease can be completely missed on aspiration if the needle lands between affected areas. The trephine shows the whole picture.
  • Results go to your haematologist — The two samples go to different laboratories and are interpreted together by your treating doctor.
4.8 · 800+ Google reviews · 15,000+ patients treated
Limited Slots Today

Talk to a medical oncologist

₹950   Today: FREE  ·  Including free written second opinion

Reply within 2 working hours
Report reviewed by a senior oncologist
Confidential. No commitment to start treatment.
or
Call 1800 202 8726
17+
Cancer Specialists
on Panel
96.9%
Breast Cancer
Survival Rate*
15,000+
Patients
Treated
4.8★
Google Rating
(800+ reviews)

In a bone marrow biopsy, two samples are taken from the same site. The aspiration draws liquid marrow — individual cells that can be examined under a microscope. The trephine biopsy removes a solid sliver of bone with marrow inside it. Each answers questions the other cannot, which is why both are taken in one procedure.

What are aspiration and trephine biopsy?

Bone marrow aspiration
A fine needle is passed into the marrow cavity and a small amount of liquid marrow is drawn out. The fluid contains individual cells that can be spread onto slides and examined — their shape, chromosome pattern and surface markers can all be assessed from this sample.
Trephine biopsy
A slightly wider needle removes a thin solid cylinder of bone with the marrow tissue inside it. Because the sample stays intact, the laboratory can see how cells are arranged within the bone — their density, their distribution, and whether abnormal cells have grown in concentrated patches.
The procedure site
Both samples are collected from the back of the hip bone, called the posterior iliac crest, in the same visit. Local anaesthetic numbs the skin and bone surface. The aspiration may cause a brief sharp sensation as the marrow is drawn — this is expected and lasts only a second or two.

What does each sample show that the other cannot?

The aspiration gives a close-up of individual cells. The laboratory can identify what type of cell is abnormal, look at chromosomes for changes linked to specific diagnoses, and test surface markers that distinguish one blood cancer from another.

The trephine gives the wider picture. It shows how full the marrow is — called cellularity — and whether abnormal cells are distributed evenly or in concentrated patches. Patchy infiltration can be completely missed on aspiration if the needle happened to land between unaffected areas.

Fibrosis — scarring of the marrow — can make the aspiration impossible to interpret, while the trephine still gives usable tissue. Some conditions show clearly on aspiration and very little on trephine, and the reverse is equally true.

Not sure what this means for you?

Share your reports and a senior oncologist will explain your options in plain language — no obligation to start treatment.

Meet the Specialists

17+ senior cancer specialists. One panel for your case.

Trained at AIIMS, Tata Memorial, and leading international centres. Combined 150+ years of experience. Every complex case is reviewed by 3+ of them — together.

Dr. Naresh Gundu
Medical Oncologist

Dr. Naresh Gundu

MBBS, DNB (Internal Medicine), DM (Medical Oncology)

View Profile
Dr. C. Raghavendra Reddy
Medical Oncologist

Dr. C. Raghavendra Reddy

MBBS(Gold Medal), DNB(General Medicine), DM(Medical Oncology)(Gold Medal)

View Profile
Dr. Bharati Devi Gorantla
Medical Oncologist

Dr. Bharati Devi Gorantla

MBBS, MD(General Medicine), DM(Medical Oncology)(Adyar,Chennai), ECMO, MRCP SCE(UK)

View Profile
Dr. Owais Mohammed
Medical Oncologist

Dr. Owais Mohammed

MBBS, MD (General Medicine), DrNB (Medical Oncology), ECMO, MRCP SCE (Medical Oncology) (UK)

View Profile
Dr. T. Raghavender Reddy
Medical Oncologist

Dr. T. Raghavender Reddy

MBBS, DM (Medical Oncology), MD (Radiation Oncology)

View Profile
Dr. N. Kiranmayee
Medical Oncologist

Dr. N. Kiranmayee

MBBS, DM (Medical Oncology), MD (Internal Medicine)

View Profile
Dr. Muralidhar Muddusetty
Surgical Oncologist

Dr. Muralidhar Muddusetty

MBBS (AIIMS), MS (Surgery) (AIIMS), DNB (Surgical Oncology), MRCS (Edinburgh)

View Profile
Dr. Raghavendra Naik
Surgical Oncologist

Dr. Raghavendra Naik

MBBS, MS (General Surgery), M.Ch (Surgical Oncology)

View Profile
Dr. Mohammed  Imaduddin
Surgical Oncologist

Dr. Mohammed Imaduddin

M.B.B.S, MS (General Surgery), M.Ch (Surgical Oncology)

View Profile
Dr. Vinay Mamidala
Surgical Oncologist

Dr. Vinay Mamidala

MBBS, MS(General Surgery), M.Ch(Surgical Oncology), FMAS, FARIS(Ongoing)

View Profile
Dr. Paila Gowri Naidu
Surgical Oncologist

Dr. Paila Gowri Naidu

MBBS, MS (General Surgery), M.Ch (Surgical Oncology), FMAS

View Profile
Dr. Venkata Sushma P
Radiation Oncologist

Dr. Venkata Sushma P

MBBS, MD (Radiation Oncology)

View Profile
Dr. Kirti Ranjan Mohanty
Radiation Oncologist

Dr. Kirti Ranjan Mohanty

MBBS, MD (Radiation Oncology)

View Profile
Dr. Gangadhar Vajrala
Radiation Oncologist

Dr. Gangadhar Vajrala

MBBS, MD (Radiation Oncology), MPH

View Profile
Dr. Basudev Pokhrel
Hematologist

Dr. Basudev Pokhrel

MBBS, M.D (Immunohematology & Blood Transfusion)

View Profile
Dr. Mohammed Imran
Interventional Radiologist

Dr. Mohammed Imran

View Profile
Dr. Vajja Sandeep Kumar
Surgical Oncologist

Dr. Vajja Sandeep Kumar

MBBS, MS (General Surgery), DrNB (Surgical Oncology), FALS Oncology

View Profile
Dr. Sridhar Kamani
Surgical Oncologist

Dr. Sridhar Kamani

MBBS, MS (General Surgery), DrNB (Surgical Oncology)

View Profile

Want a specific doctor for your case? Mention them when booking.

Book Free Consultation

You do not have to work this out alone

A 45-minute consultation with a specialist who treats this every week.

Book Free Consultation Call 1800 202 8726

Why are both samples taken at the same time?

Collecting both samples together means one visit, one prepared site, and no delay in getting the full picture. Scheduling them separately would mean two procedures on different days and a gap before your doctor has everything needed to proceed.

There is also a practical reason. If the aspiration produces a dry tap — no usable fluid, which can happen when marrow is very packed or scarred — the trephine is already being collected and still gives the laboratory solid tissue to work with.

Together, the two samples give your haematologist what neither provides alone: the cellular detail from the aspiration and the structural picture from the trephine.

What happens to the samples after they are collected?

The aspiration fluid goes to several different laboratories. Some is processed quickly for an initial look. The rest goes to specialist units for chromosome analysis and surface-marker testing, which take longer by the nature of those tests.

The trephine core must be chemically processed before it can be cut into thin slices and stained — this takes a number of days. Your results are collected by your treating haematologist, who reads the aspiration and trephine findings together. Your team will tell you which results are expected first and when the full report is likely to be ready.

Explore 62 more Biopsy Techniques and How They Compare topics

All Biopsy Techniques and How They Compare →

Next step

Still not sure what applies to you?

Send your reports across and a senior medical oncologist will go through what they mean, what is known, and what the options actually are.

Book Free Consultation Call 1800 202 8726
Common questions

Frequently asked questions

Will I feel the aspiration and the trephine differently?

Most people describe the aspiration as a brief sharp pulling sensation lasting a second or two as the marrow is drawn. Local anaesthetic prevents pain at the skin and bone surface but cannot fully block the sensation from inside the marrow cavity — this is expected, not a sign that anything went wrong. The trephine involves more pressure than sharp pain. The area may ache for a day or two afterward, which is normal and usually settles without any specific treatment.

Why does the bone marrow report take so long to come back?

The two samples go to different laboratories, and some tests take time by nature. The trephine core must be chemically softened before it can be cut into slides, which alone takes several days. Chromosome analysis on the aspiration fluid takes longer still. Your haematologist receives individual results as they arrive and interprets the full picture when everything is in. It is reasonable to ask your team which results are expected first and what the likely timeline is.

Can the aspiration alone give enough information without a trephine?

Occasionally, yes — if a diagnosis is already clear from blood tests and a straightforward aspiration confirms it. For most assessments, including staging and monitoring, the trephine adds information the aspiration cannot provide, particularly when patchy disease is a possibility. The decision is made by your haematologist based on what question they need the procedure to answer, not by a fixed rule that applies to every situation.

What does a dry tap mean?

A dry tap means no usable fluid was drawn during the aspiration. It can happen when the marrow is very densely packed with cells, when there is significant fibrosis, or occasionally for technical reasons specific to that attempt. It is not a sign that something went wrong with the procedure itself. The trephine biopsy is still collected and usually provides enough solid tissue for the laboratory to work with and reach a result.

What does cellularity mean on a bone marrow report?

Cellularity describes how much of the marrow space is filled with blood-forming cells compared with fat. A hypercellular marrow has more active cells than expected for your age; a hypocellular marrow has fewer. What is considered normal changes with age, so the laboratory takes that into account when reporting it. The figure helps your haematologist understand whether disease has crowded out normal marrow tissue or whether the marrow has become underactive.

Why is bone marrow taken from the hip rather than somewhere else?

The back of the hip bone contains a large, flat area of marrow that sits close to the skin surface and is straightforward to reach safely. It is well away from major nerves and blood vessels, which keeps the risk of complications low. In some situations — such as in young children or when the hip cannot be used — another site may be chosen. But the posterior iliac crest is the standard site for adults because it reliably gives a good sample with minimal risk.

Full index

Browse all 701 biopsy topics

Every page in this section, grouped by the part of the journey it belongs to. Pick a group to see what is in it.

What Is a Biopsy?

What Is a Biopsy? Everything You Need to Know →

Types of Biopsy Compared

Which Biopsy Will You Have? Techniques Compared →

Preparing for a Biopsy

What to Expect on the Day of Your Biopsy →

Recovery and Aftercare

After a Biopsy: Recovery, Aftercare and Warning Signs →

Biopsy by Body Part

Biopsy by Body Part: What to Expect at Each Site →

Understanding Your Report

How to Read a Biopsy Report: Terms Explained →

IHC and Molecular Markers

IHC and Molecular Markers on a Biopsy: What They Mean →

Grading and Scoring Systems

Cytology & Prostate Scoring Systems Explained →

How Accurate Is a Biopsy?

How Accurate Is a Biopsy? Errors and Second Opinions →

If Your Result Is Benign

Your Biopsy Is Benign: What It Means and What Comes Next →

Call now Book free consultation