Diagnosis

Doctors use many tests, such as evaluations of the blood and bone marrow, to diagnose eosinophilia. Although a patient’s signs and symptoms may cause a doctor to suspect eosinophilia, it is diagnosed only by blood tests and bone marrow evaluations. Some tests may also determine which treatments may be the most effective. Your doctor may consider these factors when choosing a diagnostic test:

• Age and medical condition
  
  
• The type of cancer suspected
  
  
• Severity of symptoms
  
  
• Previous test results

The main criteria for diagnosing eosinophilic leukemia are:

• An eosinophil count in the blood greater than or equal to 1.5 x 10⁹ /L which persists over time
  
  
• The absence of parasitic, allergic, or other causes of eosinophilia
  
  
• Organ system involvement or dysfunction directly related to eosinophilia

In addition to a physical examination, the following tests may be used to diagnose eosinophilic leukemia:

Blood tests. The diagnosis of eosinophilic leukemia begins with a routine blood test to measure the number of different types of cells in a person's blood, called a complete blood count (CBC). If the blood contains high levels of eosinophils (see criteria above), eosinophilic leukemia may be present.

Bone marrow biopsy. In a bone marrow biopsy, a doctor takes a sample of marrow, usually from the back of the patient’s hipbone, with a needle after the area has been numbed. The cells from the marrow, along with the cells from the blood, are analyzed by a pathologist (a doctor who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose disease) to determine the number and type of abnormal cells. An increased number of immature cells, known as blasts, indicate an acute rather than a chronic eosinophilic leukemia.

If an increased number of eosinophils are found, a molecular genetic analysis should be done to test for a mutation that produces an abnormal protein known as FIP1-like-1/platelet-derived growth factor alpha. This could help decide the type of treatment which should be given (see Treatment).

Immunophenotyping. Immunophenotyping is the examination of the proteins on the surface of the leukemic cells and allows the doctor to confirm the exact type of leukemia.

Cytogenetics. Cytogenetics is the examination of the leukemic cells for chromosomal abnormalities. It assists in confirming the diagnosis and may help the doctor determine the person’s prognosis (chance of recovery).

Computed tomography (CT or CAT) scan. A CT scan creates a three-dimensional picture of the inside of the body with an x-ray machine. A computer then combines these images into a detailed, cross-sectional view that shows any abnormalities or tumors. Sometimes, a contrast medium (a special dye) is injected into a patient’s vein to provide better detail. A CT scan also shows enlarged lymph nodes or a swollen spleen or liver.

Evaluation of the heart. People with high eosinophil counts over a long period of time frequently have disturbances in heart function and rhythm. The doctor may recommend an electrocardiogram (ECG or EKG, a test that records the electrical activity of the heart to show whether there are abnormal rhythms or to detect damage) and/or an echocardiogram (a procedure that evaluates the structure and function of the heart using sound waves and an electronic sensor).

Learn more about what to expect when having common tests, procedures, and scans.

Find out more about common terms used during a diagnosis of cancer.