Understanding White Blood Cell Count – Normal, High, & Low

How blood cancers affect blood counts?

You may have noticed that blood cancers and leukemia can cause both a high or low white blood cell count, and you may ask how is this possible. It has to do with the natural history of the disease.

Leukemia is an alteration of the stem cells in the bone marrow. At the beginning of the disease, white blood cell counts are extremely high, much higher than we can find in common cases of infections. But such high levels do not mean your body is protected against infection, because they are non-functioning and immature cells that do not defend your body correctly. Thus, there’s a high risk of infection and an elevated white blood cell count.

But at some point, leukemia cells become stuck or infiltrated in the bone marrow. When they do, they cause severe alterations in the normal functioning of the stem cells in the bone marrow, and we will see a depletion of one or more types of blood cells. That’s why we see anemia in a late phase of leukemia, because the bone marrow is affected, and red blood cell production becomes impaired. We can also have a low count of white blood cells and platelets with associated health problems.