The Medical Diagnosis: Lymphoid or Myeloid Leukemia

A medical diagnosis for leukemia begins with a medical history and physical exam. The physician compiles a history by noting reported symptoms, and asking questions about recent infections, easy bruising, bone pain and fatigue. The physical exam may reveal signs of swelling in the spleen, liver, or lymph nodes. If a suspicion of leukemia develops from the medical history and results of the physical exam, the physician usually orders a number of tests.

A complete blood count reveals the total number of red blood cells (RBCs), white blood cells (WBCs) and platelets, while also providing information about hemoglobin levels, hematocrit (RBC concentration), and RBC size. Low RBC counts, hemoglobin, or hematocrit for instance, are associated with anemia. Although many people associate leukemia with excessive numbers of WBCs, a low white blood cell count may also be an indicator of cancer depending on the differential blood count (see below). The following is a list of the possible results from the test, and what the test results mean:

A differential blood count measures the proportions of the different types of white blood cells. Normally, the distribution of WBCs follows a characteristic pattern with neutrophils comprising 40 to 60 percent of the total WBCs, lymphocytes 20 to 40 percent, monocytes 4 to 8 percent, eosinophils 1 to 3 percent, and basophils 0.5 to 1 percent. WBC counting often helps to distinguish between inflammatory diseases and malignancy. WBC levels associated with the acute type of leukemia often have disproportionately high levels of immature WBC, or "blasts."

If blood testing suggests that further investigation is required, the next step is to analyze the bone marrow. To obtain a bone marrow aspiration, a needle is inserted into the hipbone to remove a bone marrow sample by suction. The material is then examined microscopically.

 

A core bone marrow biopsy is another form of extracting bone marrow. A larger needle is used, and a portion of the bone marrow is removed intact from the hipbone.

The tissue and liquid removed by bone marrow sampling is used to make the final medical diagnosis. Morphology, cytochemistry and immunophenotyping are used to determine the specific type of cancer cell involved. Treatment options and survival rates vary depending on whether lymphoid or myeloid leukemia is diagnosed, as well as what level of maturity the cells have reached.

 

Cell morphology refers to the cells' appearance under the microscope. Pathologists are trained to make note of tiny sub-cellular structures like chromatin, nucleoli, and granules. Cytochemistry uses a variety of methods to make a diagnosis, for example, staining cells with inks, and testing cellular levels of enzymes like terminal transferase and myeloperoxidase. Immunophenotyping makes use of specific diagnostic antibodies that detect proteins expressed on the cell surface of malignant cells.

Other tests study cells at the genetic level. Cytogenetic studies assess the number and integrity of DNA chromosomes in the cell. With the advent of modern molecular biology techniques, individual DNA gene sequences can also be studied for mutations. Specific chromosomal and genetic alterations are also an important factor in determining individual prognosis and defining appropriate treatment strategies.

Once a medical diagnosis is made, diagnostic imaging tools may be used to see if the cancer has spread into other organs. A number of diagnostic tools, including x-rays, CT scans and MRI imagery are available for this purpose.

 

Chronic leukemia progresses slower than acute varieties, and symptoms take longer to develop. Find out more at Chronic Leukemia and Symptoms.