What is an abnormally low number of leukocytes called?

An abnormally low number of leukocytes, or white blood cells, is referred to as leukopenia. Leukocytes play a crucial role in the immune system, helping the body fight off infections and other diseases. When their numbers fall below the normal range, this can impair the immune response, making the individual more susceptible to infections.

Leukopenia can result from various causes, including bone marrow disorders, autoimmune diseases, certain medications, or severe infections. It's important to recognize this condition in clinical settings, as it requires careful management to prevent potential complications due to increased vulnerability to pathogens.

The other terms listed relate to different conditions: leukocytosis refers to an increase in the number of white blood cells, leukemia is a type of cancer that affects blood and bone marrow leading to high levels of immature white blood cells, and thrombocytopenia indicates a low number of platelets in the blood. Each of these conditions has distinct implications for health, but they do not pertain to leukocyte deficiency.