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Diagnosis and tests

What the bone marrow test tells us

The related article (“Bone marrow aspiration and biopsy”) explains the doctor’s examination. This topic brings together in one place what a single bone marrow sample reveals, and why this test is essential in leukaemia.

Last updated: ~1 min read
A tube in the centre with icons.
Figure 1.One sample, many answers.

01Short answer

A bone marrow test usually provides two samples from the back of the hip bone. The aspirate (liquid marrow) is used to look at the cells (microscopy), their type (flow cytometry), their chromosomes (karyotype, FISH) and their genes (molecular tests). The biopsy, a thin core of bone, shows the structure of the marrow: how full of cells it is (cellularity), whether there is fibrosis, and how leukaemia cells are spread. At diagnosis, one sample answers several questions: is there leukaemia, what type is it, what are its genetics, and how is normal blood production doing? During treatment, repeat tests assess remission and MRD. In some leukaemias (CLL, for example) it is not always needed.

02Simple explanation

The aspirate: cells, markers, genes.

The biopsy: structure and cellularity.

Diagnosis and follow-up.

03Scientific explanation

Cellularity: the share of marrow filled with cells falls with age; in leukaemia it is often very high, and after chemotherapy it is temporarily low.

Assessing remission: fewer than 5% blasts after treatment and recovered blood counts are the main criteria for morphological remission; MRD shows a deeper response.

04What happens in the body?

One sample, many answers

One marrow sample is shared between several labs.

Aspirate and biopsy

The liquid and the core complement each other.

An aspirate and a biopsy core
Figure 2.An aspirate and a biopsy core.

Cellularity

How full the marrow is can be seen on the biopsy.

A honeycomb-like pattern.
Figure 3.Marrow cellularity — What the bone marrow test tells us

05A bone marrow test

Four steps.

Preparation — A comfortable position.1PreparationA comfortable position.
Aspirate — Liquid marrow.2AspirateLiquid marrow.
Biopsy — A core of bone.3BiopsyA core of bone.
Lab — Several tests.4LabSeveral tests.

06What one sample reveals

TestAnswer
MicroscopyBlast percentage, how cells look
Flow cytometryType, MRD
Karyotype, FISHChromosome changes
Molecular testsMutations
BiopsyCellularity, fibrosis, distribution

07Key terms

Aspirate
A sample of liquid bone marrow.
Trephine biopsy
A core sample of bone marrow.
Cellularity
The share of marrow filled with cells.
Remission
The disappearance of signs of leukaemia.
Fibrosis
An increase in fibres.

08Key points

  • A marrow test answers many questions.
  • The aspirate is for cell and gene tests.
  • The biopsy shows structure.
  • It is essential at diagnosis.
  • It assesses remission.
  • It is not equally needed in every leukaemia.

09Frequently asked questions

Why is it repeated?

To check the response to treatment and remission.

Does it hurt?

It is done under local numbing; you may feel pressure and brief pain (“Hairy cell leukemia: symptoms and diagnosis”).

When will results come?

Microscopy in days, genetics in weeks.

10Questions for your doctor

Take these questions to your appointment. The ones you save are collected on the “My questions” page and stay on this device only.

  1. Why is it repeated?

  2. Does it hurt?

  3. When will results come?

My questions

12Sources

  1. MedlinePlus. Bone marrow tests
  2. MedlinePlus. Bone marrow aspiration
  3. MedlinePlus. Bone marrow biopsy
  4. National Cancer Institute (NCI). Infection and Neutropenia during Cancer Treatment
  5. National Cancer Institute (NCI). Adult Acute Myeloid Leukemia Treatment (PDQ®) — Patient Version
  6. National Cancer Institute (NCI). Chronic Lymphocytic Leukemia Treatment (PDQ®) — Patient Version
  7. National Cancer Institute (NCI). Leukemia — Patient Version
  8. National Cancer Institute (NCI). Adult Acute Lymphoblastic Leukemia Treatment (PDQ®) — Patient Version
  9. National Cancer Institute (NCI). Chronic Myeloid Leukemia Treatment (PDQ®) — Patient Version
  10. National Cancer Institute (NCI). Childhood Acute Lymphoblastic Leukemia Treatment (PDQ®) — Patient Version
Medical disclaimerThis information is for educational purposes only and does not replace medical advice.
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