Blood and bone marrow

To understand blood cancers, it can help to know more about your blood and blood cells.

About the blood and bone marrow

To understand blood cancers (these include leukaemia, lymphoma and myeloma) and their treatment, it can help to know more about your blood and blood cells.

Blood is made up of blood cells which float in a liquid called plasma. Blood cells are made in the bone marrow. The bone marrow is the spongy material found inside our bones. Most blood cells are made in the:

  • back of the hips (pelvis)
  • backbone (spine)
  • breastbone (sternum).

The bone marrow usually makes billions of new blood cells every day to replace old and worn-out blood cells.


Bone and bone marrow
Image: Bone marrow



Types of blood cells

All blood cells are made from blood stem cells. These are blood cells at the earliest stage of their development. There are two types of blood stem cell:

  • lymphoid stem cells – which make a type of white blood cell called lymphocytes
  • myeloid stem cells – which make the other white blood cells such as neutrophils, red blood cells and platelets.


MACD190 Blood cells labelled
Image: How blood cells divide


Blood cells go through different stages of development before they are ready to leave the bone marrow. All blood stem cells develop into immature cells (called blast cells). They then develop into mature, red blood cells, platelets or white blood cells. Once this happens, they go into your blood and do different things:

  • Red blood cells contain haemoglobin (Hb). This carries oxygen from the lungs to all parts of the body.
  • Platelets help the blood to clot and prevent bleeding and bruising.
  • White blood cells fight and prevent infection. There are different types of white blood cell. The most important ones are neutrophils and lymphocytes.


Blood cell numbers

The levels of these cells in your blood are measured in a test called a full blood count (FBC). The table below gives an idea of the normal ranges for certain blood cells in a healthy adult.

 Type of cell  Levels found in a healthy person
 Red blood cells (measured in haemoglobin (Hb) levels) 130-180g/L of Hb in men
115-165g/L of Hb in women
 Platelets 150-400 x 109/L
 White blood cells (WBC) 4.0-11.0 x 109/L 
 Neutrophils 2.0-7.5 x 109/L
 Lymphocytes 1.5-4.5 x 109/L

These numbers can differ slightly between hospitals. Your doctor or nurse can tell you the normal ranges they use. The levels can also vary between people based on their age, ethnic background or sex (male or female).


Useful words to know

When you are dealing with blood cancer, you may come across lots of new words and not know what they mean.

Some of these words are explained here. If you need more information or support, you can call the Macmillan Support Line free on 0808 808 00 00.


The tiny building blocks that make up the body’s organs and tissues.

Full blood count (FBC)

A blood test that measures the number of different blood cells in the blood, including red blood cells, white blood cells and platelets.


Where doctors and technicians examine blood and tissue using special equipment.


A type of white blood cell that helps the body fight infection.


The liquid part of the blood. It carries platelets, red blood cells and white blood cells around the body.

About our information

  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Senior Medical Editor, Dr Anne Parker, Consultant Haematologist.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

The language we use

We want everyone affected by cancer to feel our information is written for them.

We want our information to be as clear as possible. To do this, we try to:

  • use plain English
  • explain medical words
  • use short sentences
  • use illustrations to explain text
  • structure the information clearly
  • make sure important points are clear.

We use gender-inclusive language and talk to our readers as ‘you’ so that everyone feels included. Where clinically necessary we use the terms ‘men’ and ‘women’ or ‘male’ and ‘female’. For example, we do so when talking about parts of the body or mentioning statistics or research about who is affected.

You can read more about how we produce our information here.

Date reviewed

Reviewed: 01 March 2022
Next review: 01 March 2025
Trusted Information Creator - Patient Information Forum
Trusted Information Creator - Patient Information Forum

Our cancer information meets the PIF TICK quality mark.

This means it is easy to use, up-to-date and based on the latest evidence. Learn more about how we produce our information.