Leukocytosis is characterized by elevated levels of which cells?

• A. Plasma
• B. Red Blood Cells
• C. White Blood Cells
• D. Platelets

Answer: (C)

Leukocytosis means an increase in white blood cells, the cells that defend the body against infection and inflammation. When the body detects a threat or inflammatory process, the bone marrow ramps up production of leukocytes, raising the total white blood cell count. That’s why the characteristic elevated cells are white blood cells.

Plasma is the liquid portion of blood, not cells, so it wouldn’t be described as elevated in leukocytosis. Red blood cells are the cells that carry oxygen; an increase there would be erythrocytosis. Platelets are involved in clotting; an elevated platelet count would be thrombocytosis.