Diagnosing acute myeloid leukaemia

Your doctor will take a sample of blood and send it to a laboratory for a full blood count (FBC). This will show whether leukaemia cells are present and whether the levels of the different types of blood cells are different from what would be expected in a healthy person.

Blood tests will also check for:

• lactate dehydrogenase (LDH), an enzyme that is released into the blood when cells are damaged or destroyed. LDH levels are usually raised in people with AML
• infections, such as HIV (human immunodeficiency virus) or hepatitis.

Blood cells develop in your bone marrow, so your doctor will check your bone marrow for signs of leukaemia. Samples of bone marrow are usually collected by either aspiration or biopsy.

Bone marrow aspiration – The doctor uses a thin needle to remove a small amount of fluid (aspirate) from the bone marrow, usually from the hipbone (pelvic bone).

Bone marrow biopsy or trephine – The doctor uses a slightly larger needle to remove a small amount of bone and marrow, usually from the hipbone.

You will be given a local anaesthetic to numb the area. To help you relax, you may be offered a light sedation that you inhale (a mild pain reliever known as “the green whistle”) or is injected through a small plastic tube inserted into a vein (cannula). You may feel drowsy after the procedure, so ask someone to drive you home. It takes up to 30 minutes to prepare for a biopsy, but the actual procedure takes only a few minutes.

The bone marrow samples are sent to a laboratory where they will be tested to work out the subtype of AML and any changes to genes (microscopic units that tell cells how to behave). Tests may include:

Immunophenotyping – This test looks for certain markers that are on the surface of leukaemia cells. Looking at the patterns of these markers can help your doctor confirm that the leukaemia is AML (and not ALL) and to work out the subtype.

Genomic and other tests – Most cancers and leukaemias develop because of gene changes on a particular cell. Genomic testing looks for these changes. Most changes occur during a person’s lifetime (acquired changes not inherited from a parent), but sometimes inherited changes are found. The results help doctors diagnose the subtype of AML, guide treatment and monitor the response to therapy. They can also help to predict if the leukaemia is likely to come back (relapse).

PCR (polymerase chain reaction) and NGS (next generation sequencing) tests look for the most common gene changes in AML. A PCR test may also be used to check how well treatment has worked. A test called FISH (fluorescence in situ hybridisation) may be used to look for abnormal chromosomes (e.g. the Philadelphia chromosome).

You may have other tests to find out more about the AML, your general health and how well your organs are working. Imaging tests may include a chest x-ray, a computerised tomography (CT) scan, ultrasound and a magnetic resonance imaging (MRI) scan.

Other tests may include:

HLA typing – If a stem cell transplant might be a treatment option for you, a blood or bone marrow sample will be tested for human leukocyte antigen (HLA). HLA is found on most cells in your body – it helps your immune system recognise which cells belong in your body. Usually, a stem cell transplant can only go ahead if the donor is a close match to your HLA type. This is why your close relatives may also have an HLA test to see if they are a match.

Gated heart pool scan – This scan shows how well the heart is working and may be used to check that you are fit enough for chemotherapy. A small amount of your blood is taken, mixed with some radioactive material and injected back into your body. A special camera takes pictures of the blood being pumped by your heart. The scan usually takes about an hour.