How leukaemia (leukemia) is diagnosed?

Leukaemia (also spelt leukemia) is diagnosed by checking samples of your blood or bone marrow for abnormal cells. The samples are then tested in different ways to find out more about any abnormal cells. Some of the tests look for changes in the genes or chromosomes inside the abnormal cells. These tests give your team more information about the exact type of leukaemia you have, and helps them plan the best treatment for you.

Waiting for test results can be a difficult time. It may take from a few hours to a couple of weeks for the results of your tests to be ready.

After diagnosis, you may also have further tests and scans:

  • to check your general health
  • to look for effects of leukaemia in other areas of the body.

Your doctor or nurse can give you more information about any tests you need. This may depend on the type of leukaemia you have. We have more information about tests and different types of leukaemia below.

Blood tests

You will have blood tests to:

  • check the numbers of the different types of blood cell – called a full blood count
  • look for leukaemia cells.

Bone marrow test

You may also have tests to check your bone marrow. Bone marrow is a spongy material that is found in the middle of the bones. A doctor or nurse can take a small sample of bone marrow from the back of the hip bone (pelvis). The sample is sent to a laboratory to be checked for abnormal cells.

We have more information about having a bone marrow test.

Diagnosis of acute myeloid leukaemia (AML)

Detailed blood or bone marrow tests for acute myeloid leukaemia (AML) include:

  • Immunophenotyping

    Immunophenotyping looks for specific proteins on the surface of leukaemia cells. It helps identify the type of leukaemia and the type of blood cell that has become abnormal. This test can also be used to look for very small numbers of leukaemia cells during, and at the end of, treatment.

  • Cytogenetics and molecular tests

    These tests look for gene changes inside the leukaemia cells. Tests may include:

    • G-banding – this is where the genetic material from a leukaemia cell is examined using a special microscope.
    • FISH (fluorescence in situ hybridisation) – this test looks for specific gene changes that may not be seen with G-banding.
    • PCR (polymerase chain reaction) – this is a very sensitive test that looks for specific gene changes that cannot be seen under a microscope. This test can also be used to look for very small amounts of leukaemia during, and at the end of, treatment.

You may also have further tests, such as:

  • Tests to check your general health

    This will include blood tests for infections such as HIV and hepatitis. You may also have x-rays to check your lungs and heart health, other heart tests, and more blood tests to check how your liver and kidneys are working.

  • Tissue (HLA) typing

    You will have this blood test if you might need a donor stem cell transplant as part of your treatment. Your healthcare team use information about your tissue type to find a possible stem cell donor for you.

  • Lumbar puncture

    A lumbar puncture is a test that checks for leukaemia cells in the fluid around the brain and spinal cord. You may have this test but it is not always needed. Together, the brain and spinal cord are called the central nervous system (CNS). The fluid is called cerebrospinal fluid (CSF). The doctor collects a sample of your CSF and sends it to the laboratory for tests.

    A lumbar puncture can also be used to inject chemotherapy into the CSF. This is called intrathecal chemotherapy. It may be done to treat leukaemia in the CNS.

Diagnosis of chronic lymphocytic leukaemia (CLL)

Detailed blood tests for chronic lymphocytic leukaemia (CLL) include:

  • Cytogenetic testing

    Cytogenetic testing looks at all the chromosomes in the leukaemia cells.

  • Fluorescent in situ hybridisation (FISH) testing

    Fluorescent in situ hybridisation (FISH) testing is an important cytogenetic test used to look for a small number of specific changes in genes or chromosomes in the CLL cells.

  • Immunophenotyping

    Immunophenotyping checks for CLL cells in the blood.

  • Immunoglobulin testing

    Immunoglobulin testing checks the levels of antibodies you have in your blood for fighting infection.

  • Direct Coombs test

    Direct Coombs test checks if the CLL cells are making antibodies that can damage your red blood cells.

You may also have further tests, such as:

  • Chest x-ray

    A chest x-rayx-ray takes a picture of your chest, to check your lungs and heart. The x-ray also looks at lymph nodes in your chest.

  • CT scan

    A CT scan takes a series of x-rays, which build up a 3D picture of the inside of the body. A CT scan is sometimes used to check how many lymph nodes are affected by CLL. It can also be used to see whether the spleen is enlarged.

  • Bone marrow biopsy

    You may have a bone marrow biopsy. This is used to check how much CLL is in the bone marrow.

  • Lymph node biopsy

    People do not usually need a lymph node biopsy. But some people may have an enlarged lymph node removed so it can be examined under a microscope. You may have this done under a local or general anaesthetic. It is a small operation and most people can go home on the same day. After the operation you have a small wound with a few stitches. The stitches are usually taken out after 7 to 10 days.

Diagnosis of acute lymphoblastic leukaemia (ALL)

Detailed blood or bone marrow tests for acute lymphoblastic leukaemia (ALL) include:

  • Immunophenotyping

    This looks for specific proteins on the surface of leukaemia cells. It helps identify the type of leukaemia and the type of blood cell that has become abnormal. This test can also be used to look for very small numbers of leukaemia cells during, and at the end of, treatment.

  • Cytogenetics and molecular tests

    These tests look for gene changes inside the leukaemia cells, including one called the Philadelphia chromosome (Ph+ ALL). Tests may include:

    • G-banding – this is where the genetic material from a leukaemia cell is examined using a special microscope.
    • FISH (fluorescence in situ hybridisation) – this test looks for specific gene changes that may not be seen with G-banding.
    • PCR (polymerase chain reaction) – this is a very sensitive test that looks for specific gene changes that cannot be seen under a microscope. This test can also be used to look for very small amounts of leukaemia during, and at the end of, treatment.

You may also have further tests, such as:

  • Tests to check your general health

    This will include blood tests for infections such as HIV and hepatitis. You may also have x-rays to check your lungs and heart health, other heart tests, and more blood tests to check how your liver and kidneys are working.

  • Tissue (HLA) typing

    You will have this blood test if you might need a donor stem cell transplant as part of your treatment. Your healthcare team use information about your tissue type to find a possible stem cell donor for you.

  • Lumbar puncture

    A lumbar puncture is a test that checks for leukaemia cells in the fluid around the brain and spinal cord. You may have this test but it is not always needed. Together, the brain and spinal cord are called the central nervous system (CNS). The fluid is called cerebrospinal fluid (CSF). The doctor collects a sample of your CSF and sends it to the laboratory for tests.

    A lumbar puncture is also used to inject chemotherapy into the CSF. This is called intrathecal chemotherapy. It may be done to treat leukaemia in the CNS. You will have this done at different times during treatment for ALL.

Diagnosis of chronic myeloid leukaemia (CML)

Detailed blood or bone marrow tests for chronic myeloid leukaemia (CML) include:

  • Philadelphia chromosome test

    Doctors use the blood and bone marrow samples they have taken to look for the Philadelphia chromosome.

  • Polymerase chain reaction (PCR) test

    This blood test looks for the BCR-ABL1 gene in the leukaemia cells. It is a very sensitive test, which can detect tiny amounts of leukaemia. It is also used during treatment for CML to check how well treatment is working.

You might also have an ultrasound scan to check the size of your spleen and liver. Ultrasound scan use sound-waves to build up a picture of the inside of 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 Editors, Dr Anne Parker, Consultant Haematologist; and Dr Helen Marr, 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.

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