A CBC (complete blood count) test is a series of tests that examines the health of various blood components. The test has many diagnostic purposes. It does not directly detect the presence of cancer in the body, but a CBC test can reveal blood abnormalities that may indicate the presence of certain cancers.
According to the peer-reviewed service Lab Tests Online, a CBC test includes an analysis of all aspects of blood health, including the overall number of white blood cells, red blood cells, platelets and the oxygen-carrying protein hemoglobin. The test also determines the amount of red blood cells in a given volume of blood, a measurement called hematocrit.
Low Red Blood Cells
A low red blood cell count or hematocrit points to the presence of anemia (lack of healthy red blood cells), according to the U.S. National Library of Medicine. In some cases, anemia indicates the development of leukemia or the bone marrow cancer multiple myeloma.
Excess White Blood Cells
Excessive production of white blood cells (leukocytosis) may also reveal the presence of leukemia.
Additionally, decreased numbers of platelets--which help give blood its clotting abilities--may be a sign of leukemia, according to Lab Tests Online.
Abnormal test results in the categories listed above may also indicate a number of other ailments, including malnutrition, infection, inflammatory disease and genetic disorders.