Red Blood Cell (RBC) Count

A red blood cell (RBC) count measures the number of red blood cells in a specific volume of blood (usually microliters). Red blood cells are the most numerous cells in the blood and contain hemoglobin, which is responsible for transporting oxygen from the lungs to the body's tissues and carrying carbon dioxide back to the body. This test, along with measuring hemoglobin and hematocrit, is the cornerstone of diagnosing and classifying anemia and polycythemia.