What does an increase in WBC count typically indicate?

An increase in white blood cell (WBC) count is typically associated with the body's immune response to various conditions, often indicating the presence of an underlying disease or infection. When the body detects pathogens like bacteria, viruses, or other foreign substances, it mobilizes white blood cells to fight off these invaders, leading to an elevated WBC count, a process known as leukocytosis. This response helps medical professionals diagnose and monitor infections and inflammatory conditions.

The other options refer to different scenarios. A normal physiological response, such as during physical exertion or stress, may not necessarily lead to a clinically significant increase in WBC count. Dehydration can concentrate blood components but does not directly reflect an increase in WBC due to disease. Lastly, a lack of infection would typically correlate with normal or low WBC counts rather than an elevated one. Thus, an elevated WBC count is primarily a signal of the body's defense mechanism reacting to disease.