How is childhood leukemia found?
At this time, there are no special tests advised for most children to help find leukemia early. The best way to find the disease early is for the parents to call the doctor right away if they notice that their child has any of the symptoms listed below.
Careful, regular medical checkups are important for children who are at higher risk of leukemia. This includes children who have been treated with chemotherapy (chemo) or radiation therapy for an earlier cancer, children who have certain genetic conditions (such as Li-Fraumeni syndrome or Down syndrome), and children who have had organ transplants.
Signs and symptoms of childhood leukemia
Childhood leukemia is often found because a child has symptoms that prompt a visit to the doctor.
Keep in mind that many of the symptoms listed here are most often caused by other problems – not leukemia. Still, it’s important to let your child’s doctor know about them so that the cause can be found and treated, if needed.
Most of the signs and symptoms of leukemia result from a lack of normal blood cells. This happens because the cancer cells crowd out the normal cells that make new blood cells in the bone marrow. The leukemia cells may also spread to other parts of the body, which can also cause symptoms.
Symptoms of leukemia can include:
- Frequent infections
- Feeling tired or weak
- Feeling cold
- Feeling dizzy or lightheaded
- Shortness of breath
- Pale skin
- Easy bruising and bleeding (such as nosebleeds or bleeding gums)
- Bone or joint pain
- Swelling of the belly
- Loss of appetite and weight loss
- Swollen lymph nodes
- Coughing or trouble breathing
- Swelling of the face and arms
- Headache, seizures, or vomiting
- Rashes or gum problems
Again, most of these symptoms are more likely to be caused by something other than leukemia, but it’s still important to have them checked by a doctor.
Tests used to find leukemia
If your child has symptoms that might be caused by leukemia, the doctor will want to do certain tests to find out if it is leukemia and, if so, what type it is. That way, treatment can be tailored to provide the best chance of success.
Medical history and physical exam
The doctor will want to know how long your child has had symptoms and might also ask about possible risk factors for leukemia.
The doctor will then check your child for any swollen lymph nodes, areas of bleeding or bruising, or signs of infection. The eyes, mouth, and nervous system may also be examined thoroughly. The doctor will feel the belly for signs of a swollen spleen or liver.
The doctor may also get a blood sample from a vein or from a “finger stick” to check your child’s blood cell counts (see below). If these are not normal and the doctor thinks your child might have leukemia, he or she could refer you to a childhood cancer doctor (a pediatric oncologist), who may run one or more tests.
Types of tests used to look for leukemia in children
Blood cell counts: Most children with leukemia have too many white blood cells and not enough red blood cells or platelets in their blood. The white blood cells they do have are often young blood cells called blasts that normally stay in the bone marrow until they are mature. Finding these blast cells in the blood, or finding very few white blood cells at all, can also make the doctor suspect leukemia. But usually a sample of bone marrow will need to be taken to be sure.
Bone marrow aspiration and biopsy: Bone marrow samples are taken by doing a bone marrow aspiration and biopsy – usually at the same time. The samples are most often taken from the hip bones, but sometimes they may be taken from other bones.
These tests use thin, hollow needles to remove small amounts of bone marrow. The area around the bone is numbed, and the child may be given a drug make them sleep during the test. The samples are sent to a lab to see if there are leukemia cells in the bone marrow.
These tests are used to find out if a child has leukemia, but they can also be used later to see if the leukemia is responding to treatment.
Spinal tap (lumbar puncture): This test is done to look for leukemia cells in the liquid around the brain and spinal cord (cerebrospinal fluid or CSF).
For this test, the doctor first numbs an area in the lower part of the back over the spine. Often the doctor gives the child medicine to make him or her sleep during the test. A small hollow needle is placed between the bones of the spine to draw out some of the fluid, which is checked for leukemia cells.
For children already known to have leukemia, a lumbar puncture can also be used to give chemotherapy drugs into the CSF to try to prevent or treat the spread of leukemia to the spinal cord and brain.
Lymph node biopsy: This test is rarely needed for children with leukemia. For this test, a whole lymph node is removed. If the node is near the skin, this is a simple operation. But it may be more complex if the node is inside the chest or belly. Most often the child will need general anesthesia (where the child is in a deep sleep).
Lab tests for leukemia
A doctor with special training will look at all of the test samples (blood, bone marrow, CSF, and lymph node tissue) under a microscope. The doctor looks at the size and shape of the cells as well as other features to tell what type they are.
A key factor is whether or not the cells look mature. Having a lot of immature cells (blasts) in the sample, especially in the blood, is a typical sign of leukemia.
The doctor also might use a number of other lab tests to diagnose and classify leukemia. You might hear some of the following terms used:
- Flow cytometry
These tests are explained in our detailed guide, Childhood Leukemia.
Other blood tests: If the child does have leukemia, other blood tests will be done to measure certain chemicals in the blood to see how well the liver, kidneys, and other organs are working. Tests may also be done to check for infections so they can be treated right away.
Imaging tests take pictures of the inside of the body. Leukemia doesn’t usually form tumors, so imaging tests aren’t as useful as they are for other types of cancer. But some of these tests might be done in children with leukemia to get a better idea of the extent of the disease or to look for other problems like infections.
Chest x-ray: A chest x-ray can help tell if the thymus or lymph nodes in the chest are swollen. It can also help look for pneumonia if the child seems to have a lung infection.
CT (computed tomography) scan: CT scans (sometimes called CAT scans) use x-rays to make detailed pictures of the inside of the body. This test can help tell if the leukemia has spread into lymph nodes in the chest or to organs like the spleen or liver.
PET/CT scan: Some machines combine the CT scan with a PET (positron emission tomography) scan. For a PET scan, a form of a slightly radioactive sugar is injected into the blood. Leukemia cells in the body are growing quickly, so they absorb large amounts of the sugar. A special camera can then create a picture showing areas of radioactivity in the body. The PET/CT scan combines the 2 pictures to give the doctor more details about any areas of cancer.
MRI (magnetic resonance imaging): An MRI is like a CT scan except that magnets and radio waves are used to make the pictures instead of x-rays. MRI scans are helpful in looking at the brain and spinal cord.
MRI scans take longer than CT scans – often up to an hour. Your child may have to lie inside a narrow tube, which can be hard for some children. Drugs are sometimes needed to help them sleep for this test. Newer, more open MRI machines may be another option, but your child will still have to lie still.
Ultrasound: Ultrasound uses sound waves to make a picture of the inside of the body. Ultrasound can be used to look for enlarged lymph nodes or organs inside the belly. This is a fairly easy test to have done. Your child simply lies on a table, and a technician moves a sort of wand over the part of the body being looked at.
Bone scan: This test is not done often for childhood leukemias, but it may be useful if the child has bone pain that might be caused by infection or cancer in the bones. It is done in a way much like a PET scan. If the child has already been found to have leukemia or if a PET scan has already been done, there is often no need for this test.
Last Medical Review: 05/13/2015
Last Revised: 02/03/2016