Canadian Society for Medical Laboratory Science (CSMLS) Practice Exam

Which condition is characterized by excessive levels of a certain type of white blood cell?

1. Anemia

2. Leukopenia

3. Leukocytosis

4. Thrombocytopenia

The correct answer is: Leukocytosis

Leukocytosis is characterized by an increase in the number of white blood cells (WBCs) in the bloodstream. This condition is often a response to stress, infection, inflammation, or other stimuli, leading the body to produce more white blood cells to help fight off pathogens or respond to injuries. Generally, a healthy immune system will regulate the number of white blood cells, and an excessive level indicates a potential underlying issue that may require further investigation or treatment. In contrast, anemia refers to a deficiency in red blood cells or hemoglobin, which affects oxygen transport but does not involve an increase in white blood cells. Leukopenia is the condition of having too few white blood cells, which may compromise the immune response. Thrombocytopenia describes a low platelet count, impacting blood clotting rather than white blood cell levels. Thus, leukocytosis distinctly identifies the scenario of having excessive levels of white blood cells.