Physicians use several tests to evaluate a child suspected of having AML. A blood test called the complete blood count (CBC) is performed first, usually by the child’s pediatrician or an emergency room physician. The pediatric oncologist generally repeats the CBC, and will order other tests as well before deciding on therapy.
Although leukemia cells may be present in the blood test, the diagnosis and classification of leukemia requires an examination of a sample of bone marrow under the microscope. The sample of bone marrow is obtained by performing a bone marrow aspirate. A bone marrow biopsy may be performed as well, as this helps in making a diagnosis when there are too few cells in the aspirate sample.
A bone marrow aspirate will provide information regarding the subtype of AML. There are 7 different subtypes of AML. These include:
- M0- early myeloblast without maturation
- M1- acute myeloblastic without maturation
- M2- acute myeloblastic with maturation
- M3-acute promyelocytic leukemia
- M4- acute myelomonocytic leukemia
- M5- acute monoblastic leukemia
- M6- acute erythroleukemia
- M7- acute megakaryoblastic leukemia
Chromosomal abnormalities: some leukemia blast cells have an abnormal number or structure of chromosomes that are not found in the rest of the body’s chromosomes. There are some types of abnormal chromosome structure that provide information regarding response to therapy.
How is the extent of disease determined?
Since AML is a cancer of the blood, it is widespread at diagnosis, and does not need to be "staged" in the same way as a solid tumor. There are no X rays that determine the extent of the disease. However, leukemia cells can also be present in the spinal fluid, which is known as Central Nervous System (CNS) disease. A special test known as a spinal tap or lumbar puncture will be performed to obtain fluid for examination.
A physical examination may reveal other organ involvement including:
- Lymph nodes
- Liver
- Spleen
- Testes
- Skin
- Gums
However, involvement of other organs other than the CNS usually has no bearing on the type of treatment given.
Nancy Bunin, MD, Children's Hospital of Philadelphia
Reviewed and edited
CureSearch Medical Editorial Board
April 2007