Tests for chronic myeloid leukemia:
When chronic myeloid leukemia (CML) is identified, many people have no symptoms. When their doctor sends blood testing for an unrelated health concern or at a normal check-up, leukemia is frequently discovered. Even when symptoms do exist, they are frequently ambiguous and non-specific.
Tests in the lab
If your signs and symptoms point to leukemia, your doctor will need to examine your blood and bone marrow to confirm the diagnosis. A vein in your arm is frequently used to draw blood. A bone marrow aspiration and biopsy remove a small sample of bone marrow. These samples are transferred to a lab, where leukemia cells are examined under a microscope.
Counts of blood cells
The complete blood count (CBC) is a test that determines the number of different cells in your blood, such as red blood cells, white blood cells, and platelets. A differential (diff) is a count of the different types of white blood cells in your blood sample that is commonly included in a CBC. Some of your blood is deposited on a slide in a blood smear to see how the cells look under a microscope.
Most persons with chronic myeloid leukemia have an excess of white blood cells, particularly myeloblasts or blasts, which are early (immature) cells. The size and structure of the cells, as well as whether or not they contain granules, will be examined by doctors (small spots seen in some types of white blood cells).
Whether the cells appear mature (like normal circulating blood cells) or immature is a crucial consideration (lacking features of normal circulating blood cells). Patients with CML may have a reduced amount of red blood cells or platelets. Even though these findings may point to leukemia, a second blood test or a bone marrow test is usually required to confirm the diagnosis.
Samples of bone marrow
Because leukemia begins in the bone marrow, examining it for leukemia cells is an important aspect of the diagnostic process. Samples of bone marrow are acquired from two tests that are normally performed at the same time.
- Aspiration of bone marrow
- Biopsy of the bone marrow
The samples are typically collected from the rear of the pelvic (hip) bone, but other bones are also utilized. If the only aspiration is required, the sternum can be used (breast bone).
You lie down on a table for a bone marrow aspiration (either on your side or on your belly). The doctor will clean the skin over the hip and then inject a local anesthetic to numb the area and the surface of the bone. This may give a stinging or burning feeling for a short time. The bone is then pierced with a thin, hollow needle, and a syringe is used to extract a little amount of liquid bone marrow. Despite the anesthesia, most patients experience some temporary discomfort.
Following the aspiration, a bone marrow biopsy is routinely performed. A little larger needle is driven deep into the bone to extract a small bit of bone and marrow. This could also result in some minor discomfort. Pressure will be administered to the biopsy site once it has been completed to help avoid hemorrhage.
These bone marrow tests are used to help identify leukemia, although they may be repeated later to see how well the disease is responding to treatment.
The percentage of blood-forming cells in a bone marrow sample is an important factor to consider. This is referred to as cellularity. Blood-forming cells and fat cells coexist in the normal bone marrow.
Hypercellular bone marrow is defined as having more blood-forming cells than normal. When there aren’t enough of these cells, the marrow is said to be hypocellular.
The bone marrow of persons with CML is frequently hypercellular due to the presence of leukemia cells. These tests may also be performed after treatment to determine how well the leukemia is responding.
Tests of blood chemistry
These tests are used to determine the level of particular substances in your blood, but they aren’t used to diagnose leukemia. They can aid in the detection of liver or renal problems caused by the spread of leukemia cells or drug side effects.
This test examines chromosomes (DNA fragments) under a microscope for any alterations. A karyotype is another name for it. Because chromosomes are best visible while cells are dividing, a sample of your blood or bone marrow must be cultured (in the lab) until the cells begin to divide. This takes time and isn’t always successful.
Each of the 23 pairs of chromosomes in normal human cells is a specific size. Many CML patients’ leukemia cells have an aberrant chromosome known as the Philadelphia (Ph) chromosome, which resembles a truncated form of chromosome 22. It’s caused by chromosomes 9 and 22 shifting parts (translocation).
FISH (fluorescent in situ hybridization) is another method of examining chromosomes. This test employs fluorescent dyes that only bind to specific genes or chromosome segments. FISH can be used to search for particular parts of the BCR-ABL gene on chromosomes in chronic myeloid leukemia patients. It may be utilized on ordinary blood or bone marrow samples without the need to culture the cells first, allowing for faster findings than traditional cytogenetics.
This is a highly sensitive assay for detecting the BCR-ABL gene in leukemia cells and determining how much of it is present. It can detect very modest quantities of BCR-ABL in blood or bone marrow cells, even when cytogenetic testing fails to find the Philadelphia chromosome in bone marrow cells.
PCR can be utilized to aid in the diagnosis of chronic myeloid leukemia. It’s also useful to check for BCR-ABL gene copies following treatment to see if they’re still present. Though copies of this gene are discovered, it suggests the leukemia is still there, even if the cells aren’t visible under a microscope.
Images of the inside of your body are obtained through imaging examinations. They aren’t required to diagnosis CML, but they can help determine the cause of symptoms or determine whether the spleen or liver are enlarged.
A CT scan can reveal any enlarged lymph nodes or organs in your body. It isn’t required to diagnose chronic myeloid leukemia, but it may be performed if your doctor fears the leukemia is spreading to an organ, such as your spleen.
A CT scan can sometimes be used to precisely guide a biopsy needle into a suspected abnormality, such as an abscess. You stay on the CT scanning table for this process, which is called a CT-guided needle biopsy, while a radiologist slides a biopsy needle through your skin and toward the mass.
Magnetic resonance imaging (MRI) is a type of imaging that (MRI)
MRIs are extremely useful for examining the brain and spinal cord.
Ultrasound can be used to examine for enlarged organs inside your abdomen (belly), such as the kidneys, liver, and spleen, as well as lymph nodes on the surface of your body.