What test is performed to determine the packed red blood cell volume?

The hematocrit test is specifically designed to measure the volume percentage of red blood cells in a given volume of blood. It provides important information about the red blood cell mass, helping to evaluate conditions such as anemia, polycythemia, and other blood disorders. In this test, a blood sample is typically centrifuged to separate the components, allowing for direct measurement of the red blood cells in relation to the total blood volume.

While other tests, such as a complete blood count, may include information about red blood cells, they do not focus solely on packed red blood cell volume. A blood smear is used for a qualitative analysis of blood cells, assessing their shape, size, and appearance, but it does not quantify packed red cell volume. The reticulocyte count measures the number of immature red blood cells but does not provide the volume percentage of red blood cells. Thus, the hematocrit test stands out as the definitive test for determining packed red blood cell volume.