Which test determines the proportion of red blood cells in blood?

The hematocrit calculation is the test that determines the proportion of red blood cells in the blood. This test measures the percentage of blood volume that is made up of red blood cells (RBCs). It is an important parameter because it helps assess a person’s overall blood health, indicating conditions like anemia or polycythemia.

During the hematocrit test, blood is drawn and spun in a centrifuge. The spinning separates the components of blood based on density, allowing the measurement of the volume of red blood cells in relation to the total blood volume. A higher or lower than normal hematocrit can signal various health issues, emphasizing the significance of this measurement in clinical practice.

In contrast, hemoglobin determination focuses specifically on measuring the amount of hemoglobin, a protein within red blood cells that carries oxygen, rather than the proportion of red blood cells themselves.

The white blood cell differential count analyzes the types and proportions of different white blood cells, which is not related to the proportion of red blood cells. Similarly, the total white blood cell count quantifies the overall number of white blood cells in the blood but again does not provide information about red blood cell concentration.