When physicians suspect that an individual may have a type of myeloid malignancy they will obtain a detailed medical history and perform a complete physical examination. During the physical examination, the physician may inspect the lymph nodes, spleen and liver for swelling.

Following the exam, a variety of tests may be ordered to diagnose and classify the disease. Samples of cells from the blood and bone marrow will be examined and additional tissue and cell samples may be obtained to guide treatment. For a diagnosis of myelodysplastic syndrome or juvenile myelomonocytic leukemia (JMML), a child must have less than 20 percent blasts (immature cells) in the bone marrow. The presence of more than 20 percent blasts is required for a diagnosis of acute myeloid leukemia (AML).

Common tests include:

• Complete blood count (CBS) and blood smear. A CBC is a blood test that measures the number of red blood cells, white blood cells and platelets in a sample of blood. A blood sample can also measure other elements, such as the amount of hemoglobin in the red blood cells. A blood smear is the examination of cells under a microscope. It is used to detect the presence of blast cells as well as any abnormalities.
  
  
• Blood chemistry tests. These tests measure the level of specific chemicals in the blood. They are used to monitor changes in liver or kidney function caused by disease or treatment with certain chemotherapy drugs. The tests may also be ordered to determine whether treatment is required to correct abnormally low or high levels of certain minerals.
  
  
• A bone marrow aspiration and biopsy. A bone marrow aspiration involves using a needle to collect a small sample of liquid bone marrow. A bone marrow biopsy uses a larger needle to remove a piece of bone marrow, both under local anesthesia. Usually performed at the same time, these procedures may be ordered to diagnose leukemia and myelodysplastic syndromes and to classify the disease. The test may be used after diagnosis to monitor treatment or to determine if a child’s myelodysplastic syndrome is transforming into AML or is in remission.
  
  
• Tumor biopsy. A biopsy of cells in chloroma may be done. Chloroma are painless blue-green lumps that may appear around the eyes of children with AML. In addition, biopsies may be performed on other suspected tissue, including areas of the skin or organs.
  
  
• Lymph node biopsy. This procedure involves removing all or part of a lymph node and examining its tissue for cancer cells under a microscope. Malignant cells in the lymph node indicate that the cancer has spread into the lymphatic system and can invade organs in the body.
  
  
• Lumbar puncture. Also known as a spinal tap, this procedure uses a needle to remove a sample of cerebrospinal fluid (CSF) from between the bones in the lower spine. CSF is the fluid that flows around the brain and spinal cord. The sample is then examined for cancer cells. This test may be used to determine if the cancer has spread outside of the blood and bone marrow.
  
  
• Biopsy of the testicles, ovaries or skin. This procedure involves removing cells or tissue from the testicles, ovaries or skin. The sample is then examined under a microscope for signs of cancer. These tests may be ordered to detect if cancer has spread outside of the blood and bone marrow when a physician notices abnormalities in one of these areas during a physical examination.  

Additional tests which may be used to diagnose and classify myeloid malignancies include the following:

• Flow cytometry. This procedure uses fluorescent antibodies to detect certain molecules on the surface of leukemia cells. The cells are then measured and analyzed by a computer. 
  
  
• Cytogenetics. This test uses a microscope to evaluate the characteristics of cells including their formation, function and structure. It may be ordered to determine if the cells have too many chromosomes, or if the chromosomes have any abnormalities.
  
  
• Molecular genetic studies. These tests examine leukemia cell DNA. Molecular genetic studies are useful in classifying leukemia and myelodysplastic syndromes because many of their subtypes have distinctive DNA.

In addition to diagnosing and classifying myeloid malignancies, cytogenetics and molecular genetic studies may be useful in determining a person’s risk of developing such diseases. Genetic tests are currently available to identify certain genetic abnormalities, and additional genetic tests are being developed.

Leukemias rarely form visible tumors or discrete lumps or masses in internal organs - diffuse (generalized) swelling of these organs is more common. For that reason, imaging tests have limited value. If imaging tests are done on children with myeloid malignancies, they are usually conducted to diagnose infections, metastasis, or other cancer–related problems. Imaging tests that may be ordered include:

• Chest x-ray. Uses low doses of radiation to produce images of the chest on film paper or fluorescent screens. It can reveal signs of a lung infection and detect enlarged lymph nodes in the chest.
  
  
• CAT scan (computed axial tomography, also known as CT scan or computed tomography). Allows for multiple x-rays to be taken from different angles around a patient. CAT scans can detect enlarged organs, large collections of cancer cells and abscesses (collections of pus caused by an infection). CAT scans may also be used to guide a biopsy needle into an enlarged lymph node located deep in the body. This procedure is known as a CT-guided needle biopsy.

• Magnetic resonance imaging (MRI). Uses a powerful magnetic field to create images of structures and organs within the body allowing a computer to produce very clear cross-sectional or three-dimensional images. It may be ordered to determine if the disease has spread to the spinal cord, brain or other areas. As with CAT scans, a contrast material may be used to provide a more detailed image.
  
  
• Gallium scan and bone scan. Involves an injection of a radioactive substance that may be absorbed by areas of the body where cancer cells are present or bone is damaged. A scanner detects where the radioactive material has accumulated in the body and the image is recorded on film. The tests may be ordered when a child has bone pain that may be due to cancer or an infection.
  
  
• Ultrasound. Uses high-frequency sound waves to produce images of internal organs. This test is useful for detecting enlarged kidneys, liver or spleen in individuals with suspected leukemias.