Our doctors explain how leukemia is diagnosed.
At Memorial Sloan Kettering we are committed to giving you the most-accurate prognosis and best treatment recommendations possible —whether that means using existing drugs such as chemotherapy or recommending a clinical trial.
We routinely test our patients for a large panel of genetic mutations known to be found in a wide range of leukemias.
Our doctors perform a variety of tests to diagnose leukemia and determine its type and subtype. These tests that can reveal abnormalities in the appearance of cells and the amounts of different types of blood cells in circulation, changes in the bone marrow, or specific alterations in the genetic and molecular makeup of the diseased cells.
Tests we may recommend include:
- cytogenetic studies to look for chromosomal changes in cells
- immunohistochemistry studies, in which antibodies are used to distinguish between types of cancer cells
- flow cytometry, which involves passing cells through a laser beam for analysis
- molecular genetic studies, which are highly sensitive DNA and RNA tests to determine specific genetic traits of cancer cells
In order to do these tests, physicians need to collect blood and tissue samples. There are several procedures that allow them to obtain these samples.
Blood tests can show whether the amounts of various components of blood are within normal ranges. For example, patients with leukemia may have low numbers of red blood cells, which causes anemia; platelet levels may be low, leading to bleeding and bruising; and white blood cell levels may be diminished, which can lead to frequent infections.
These tests help determine the number of immature cells (blasts) in your bone marrow, and can reveal other features of leukemia cells as well. Doctors perform a bone marrow biopsy by inserting a hollow needle into the hip bone to remove a small piece of bone marrow for examination. In a bone marrow aspirate, they withdraw a small sample of liquid bone marrow through a syringe.
If doctors find diseased cells in the bone marrow, they will also typically perform a lumbar puncture, or spinal tap, to see if leukemia cells are in the fluid that surrounds the brain and spinal cord (cerebrospinal fluid).
Additional Tests & Procedures
Doctors sometimes use imaging tests including chest x-rays, ultrasound, CT scans, MRI, and PET scans to determine whether leukemia cells have affected the bones or organs such as the kidneys, the brain, or the lymph nodes.
In addition, a physical exam is an important part of diagnosis for leukemia. Your doctor will check the lymph nodes, spleen, and liver because leukemic cells can accumulate in these spots and cause swelling.
There are three primary types of ALL, B-lineage ALL, T-lineage ALL, and Burkitt leukemia. Between 20 and 30 percent of adult patients with B-lineage ALL have a type of ALL called Ph-positive ALL, characterized by the presence of the Philadelphia chromosome.
As part of diagnosis at MSK, we’ll tell you which type of ALL you have and also test for the presence of genetic mutations. About 50 percent of T-ALL cases demonstrate the presence of mutations in a gene called Notch1.
Doctors categorize AML into several broad groups.
- AML with certain genetic abnormalities, such as a translocation between chromosomes 8 and 21, a translocation or inversion in chromosome 16, changes in chromosome 11, or acute promyelocytic leukemia (M3), which usually has a translocation between chromosomes 15 and 17
- AML with multilineage dysplasia. This form of the disease is thought to evolve from a preleukemic condition known as myelodysplastic syndrome
- AML related to previous chemotherapy or radiation.
- AML not otherwise specified. These subtypes include: undifferentiated AML (M0), AML with minimal maturation (M1), AML with maturation (M2), acute myelomonocytic leukemia (M4), acute monocytic leukemia (M5), acute erythroid leukemia (M6), and acute megakaryoblastic leukemia (M7). Subtypes M2 and M4 each account for 25 percent of AML cases; M1 accounts for 15 percent; M3 and M5 each account for 10 percent of cases; the other subtypes are rarely seen
The prognosis of and therapeutic approach to the above subtypes of AML are primarily influenced by the presence or absence of particular chromosomal abnormalities and/or gene mutations.
As part of diagnosis at MSK, we’ll tell you which type of ALL you have and also test for the presence of 30 genes known to be recurrently mutated in AML. The results of these tests allow us to give you a great amount of information about your prognosis and, potentially, make clinical trials recommendations for drugs that target any genetic mutations we find.
CLL is classified, or staged, according to how far the disease has progressed. These categories are based on the following signs and symptoms:
Stage 0: Lymphocyte counts are elevated (to more than 5,000 per cubic millimeter).
Stage I: Patients have both elevated lymphocyte counts and enlarged lymph nodes.
Stage II: In addition to elevated lymphocyte counts, patients have an enlarged liver or spleen, with or without enlarged lymph nodes.
Stage III: Patients have elevated lymphocyte counts and a low red blood cell count (anemia), with or without swollen lymph nodes, and an enlarged liver or spleen.
Stage IV: Patients have elevated lymphocyte counts and a low number of blood platelets.
In addition to an assessment for abnormal blood counts and enlargement of lymph nodes and organs as outlined above, your doctor will also ask about other symptoms that can be caused by CLL, such as fevers, drenching night sweats, unintentional weight loss, and fatigue.
Doctors classify CML into three phases, which are usually defined by the percentage of immature cells, or blasts, in the bone marrow, as well as other features.
Chronic Phase: During this earliest stage of the disease, patients have a low number of blasts, or immature cells, within the bone marrow. Blasts make up less than 5 percent of all bone marrow cells. Symptoms in the chronic phase are often mild or completely absent. Most CML patients are diagnosed during this phase.
Accelerated Phase: The number of blasts rises to between 5 and 19 percent of all bone marrow cells. Patients may develop symptoms including fever, weight loss, and a decrease in appetite because the spleen is enlarged.
Blast Phase: When the number of blasts increases to more than 20 percent of bone marrow cells, patients are considered to be in the blast phase, sometimes called a blast crisis. This phase of the disease is difficult to treat.
When determining the phase, doctors also take into account the presence of any chromosomal abnormalities. For example, if a patient has two Philadelphia chromosomes the disease is usually diagnosed as accelerated-phase disease even if the blast count is less than 5 percent.