A physician who suspects that a patient may have leukemia will first obtain the patient’s medical history and perform a complete physical examination. During the physical examination, the physician will inspect the lymph nodes, spleen and liver for swelling.

Next, a variety of tests may be ordered to diagnose, classify, and monitor leukemia. Common tests include:

• Blood tests. A complete blood count (CBC) measures the number of red blood cells, white blood cells and platelets in a sample of blood, as well as the amount of hemoglobin in the red blood cells and a number of other factors.  A blood cell count and the examination of cells under a microscope may be ordered to determine if leukemia is present. Changes in the numbers of different blood cell types and the appearance of the cells can suggest leukemia.
  
  
• Bone marrow tests. A bone marrow aspiration and biopsy may be ordered. A bone marrow aspiration involves using a thin needle to collect a small sample of liquid bone marrow under local anesthesia. A bone marrow biopsy uses a larger needle to remove a piece of bone marrow.  Usually performed at the same time, these procedures may be ordered to determine if leukemia is present or to monitor treatment.
  
  
• Excisional lymph node biopsy. This surgical procedure involves removing one or more lymph nodes for examination and analysis of tissue by a pathologist.
  
  
• 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. The sample is then examined for leukemia cells. The procedure may also be ordered to deliver chemotherapy drugs into the spinal fluid when leukemia cells are located.
  
  
• 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 leukemia or treatment with certain chemotherapy drugs.
  
  
• Chest x-ray. This test uses low doses of radiation to produce images of the chest and can reveal signs of leukemia in the lungs or chest.
  

Additional tests include laboratory tests to diagnose and classify the leukemia. All biopsy samples (bone marrow, lymph node tissue, blood and CSF) are studied under a microscope. A number of characteristics, including the size and shape of the cells are noted in order to classify the cancer cells into specific types. Additional tests may also be ordered to study the chromosomes (cytogenetics) and additional substances in the cells.