Chronic Lymphocytic Leukemia (CLL)

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Diagnosing CLL

When diagnosing chronic lymphocytic leukemia, your doctor will first take a careful and complete medical history and then perform a physical exam to determine your overall health and to look for suspicious signs, such as swollen lymph nodes or an enlarged spleen. Next, your doctor will order a number of tests to help in the diagnosis.These tests may include some of the following.

Complete Blood Count (CBC)

This test examines blood for the number of red blood cells, white blood cells and platelets, and the amount of hemoglobin (protein that carries oxygen) in your red blood cells, and the percentage of your blood consisting of red blood cells. 

Cytogenetic Analysis

Your blood or bone marrow cells are examined under a microscope for changes in the chromosomes. Sometimes a chromosome is missing a part, which makes the cell behave abnormally.

Fluorescent in Situ Hybridization (FISH)

This is a special test that uses fluorescent dyes that attach to specific parts of certain chromosomes. More chromosomal abnormalities can be seen under a microscope using this technique. The information obtained from the FISH analysis helps to distinguish CLL from other forms of leukemia or lymphoma. This test also helps determine whether your CLL is a more aggressive or less aggressive form of the disease.


This test helps your doctor find out whether your increase white blood cell count is due to a reactive process such as fighting off infection or to cancer. Immunophenotyping can also determine whether you have CLL or another form of leukemia or lymphoma.

Bone Marrow Aspiration and Biopsy

A sample of your bone marrow, blood and a small piece of bone are taken from your hipbone using a hollow syringe. The cells will then be examined under a microscope to see if leukemic cells are present. You will have some pain at the site, but this is a short procedure that provides your doctor with valuable information about your bone marrow and blood cells. Your doctor may use this test to see how far the CLL has progressed or later to see how well treatment is working.

Flow Cytometry

Flow cytometry is an important test because it helps determine what types of cells are in a blood sample. The sample is treated with special antibodies (immune system–related proteins) that attach to certain substances on the cell surface. When these cells with the antibodies attached are passed by a laser beam, they give off light. A computer then analyzes and sorts the cells. Flow cytometry is also called immunocytochemistry.

New lab tests using flow cytometry have been developed that can distinguish between the slow-growing CLL cells and the more aggressive, faster-growing CLL cells. These tests look for a protein called ZAP-70 and for a substance called CD38. Low amounts of ZAP-70 and CD38 indicate the slower-growing form of CLL.

Computed Tomography (CT) Scan

A CT scanner rotates around you taking many X-rays. Then a computer combines the pictures and produces detailed cross-sectional images of the area of your body being studied. Your doctor may use this test to look for enlarged lymph nodes that cannot be felt or to see if any other organs are enlarged.  

Magnetic Resonance Imaging (MRI) Scan

Instead of X-rays, an MRI uses radio waves and very strong magnets that a computer translates into detailed images. Your doctor may use this study to examine your brain and spinal cord for signs of cancer.


An ultrasound examination uses sound waves and their echoes to create pictures of your internal organs. These images appear on a computer screen and can be reviewed at the time of the procedure or later. Your doctor may use this exam to look for enlarged organs.

Chest X-Ray

Your doctor may use a standard chest X-ray to look for any infections in your lungs.