Childhood AML diagnosis

How is childhood AML diagnosed?

AML is diagnosed by examining samples of your child’s blood and bone marrow.

Full blood count

The first step in the diagnosis is a simple blood test called a full blood count (FBC) or complete blood count (CBC).  This involves a sample of blood from a vein in your child’s arm being sent to the laboratory for investigation.  Most children with AML have a low red cell and platelet count.

Many of the white blood cells may be abnormal leukaemic blast cells and the presence of these blast cells suggests you have AML. An AML diagnosis needs to be confirmed by examining the cells in the bone marrow.

Bone marrow examination

If the results of the blood tests suggest AML, a bone marrow biopsy may be required to help confirm the diagnosis. A bone marrow biopsy involves taking a sample of bone marrow (usually from the back of the hip bone) and sending it to the laboratory for examination under the microscope.

The bone marrow biopsy may be done in the clinic or day procedure centre and is usually performed under a light anaesthetic or sedation given through a small drip in your child’s arm. The sample of bone marrow is examined in the laboratory to determine the number and type of cells present and the amount of haematopoiesis (blood-forming) activity taking place there.

An AML diagnosis is confirmed by the presence of an excessive number of blast cells in the bone marrow.

Cerebrospinal fluid examination (lumbar puncture)

A small sample of the cerebo-spinal fluid (CSF) that surrounds your child’s brain and spinal cord is collected under anaesthetic during a procedure called a lumbar puncture, and tested in the laboratory to check for the presence of cancer cells within the central nervous system (CNS).

If cells are found, additional treatment is given to the CNS. The CSF is usually negative but even in this case some CNS-directed treatment (CNS prophylaxis) is required as a very small number of cells may be present but not detectable.

Further Testing

Once the diagnosis of AML is made, blood and bone marrow cells are examined further using special laboratory tests.  These include immunophenotyping and cytogenetic tests. These tests provide more information about the exact type of AML your child has, the likely course of the disease and the best way to treat it.

Other tests may be conducted to provide information on your child’s general health and how their vital organs are functioning. These include a combination of further blood tests and imaging tests (x-rays, scans and ECG).

These results will provide a baseline of your child’s disease and general health, which will be compared with later results to assess how well your child is progressing and responding to treatment.