What is polycythemia?

What is polycythemia?

• A. Decreased volume of red blood cells
• B. Increased volume of red blood cells
• C. Normal volume of red blood cells
• D. Decreased platelets

Answer: (B)

Polycythemia means there is more red blood cell mass in the blood, leading to higher hematocrit and hemoglobin. This reflects an increased volume of circulating red blood cells, not just a change in their per-cell size. It can be due to true increases in RBC production (absolute polycythemia, as in polycythemia vera or secondary to hypoxia) or a relative increase from plasma volume loss. The option describing an increased volume of red blood cells fits this concept. Decreased red blood cell volume points to anemia, normal red cell volume does not describe polycythemia, and decreased platelets refer to thrombocytopenia.

Polycythemia means there is more red blood cell mass in the blood, leading to higher hematocrit and hemoglobin. This reflects an increased volume of circulating red blood cells, not just a change in their per-cell size. It can be due to true increases in RBC production (absolute polycythemia, as in polycythemia vera or secondary to hypoxia) or a relative increase from plasma volume loss. The option describing an increased volume of red blood cells fits this concept. Decreased red blood cell volume points to anemia, normal red cell volume does not describe polycythemia, and decreased platelets refer to thrombocytopenia.