What condition involves an excessive number of white blood cells in the body?

Leukocytosis refers to an increase in the number of white blood cells (WBCs) in the bloodstream, which can be indicative of a variety of conditions, including infections, inflammation, or even more serious disorders like leukemia. This increase in white blood cells is part of the body’s immune response, allowing it to combat pathogens or respond to other challenges.

In the context of the choices provided, leukocytosis is characterized by an elevated white blood cell count beyond the normal range. This can help physicians determine the underlying cause of the body's response to illness or stress. Understanding the normal range of white blood cells is crucial for diagnosing various conditions, especially since a significant increase can also point towards malignant processes such as blood cancers.

Other terms like leukopenia refer to a decrease in white blood cells, neutropenia specifies a reduction in neutrophils (a type of white blood cell), and anemia is related to a low number of red blood cells or hemoglobin, not white blood cells. These terms represent different blood cell conditions, highlighting the importance of white blood cell count in assessing health.