Which test determines the percentage distribution of white blood cell types?

Which test determines the percentage distribution of white blood cell types?

• A. Mean Corpuscular Volume
• B. Platelet Count
• C. Hematocrit
• D. Differential Leukocyte Count

Answer: (D)

The test that reveals the makeup of white blood cells as percentages is the differential leukocyte count. It classifies each white blood cell into its type—neutrophils, lymphocytes, monocytes, eosinophils, and basophils—and expresses each type as a percentage of the total white cell count. This helps show patterns such as neutrophilia in bacterial infections or eosinophilia in allergies or parasitic infections, and it can alert clinicians to inflammation or hematologic issues. Manual differential counting is often done by examining a stained blood smear and tallying about 100 white cells, while automated systems can classify cells as well. Absolute counts for each type can accompany the percentages, but this test’s primary purpose is the distribution of white cell types. The other tests focus on red blood cells or platelets—Mean Corpuscular Volume measures red cell size, Platelet Count counts platelets, and Hematocrit indicates the proportion of blood volume made up by red blood cells—so they do not describe the white cell composition.

The test that reveals the makeup of white blood cells as percentages is the differential leukocyte count. It classifies each white blood cell into its type—neutrophils, lymphocytes, monocytes, eosinophils, and basophils—and expresses each type as a percentage of the total white cell count. This helps show patterns such as neutrophilia in bacterial infections or eosinophilia in allergies or parasitic infections, and it can alert clinicians to inflammation or hematologic issues. Manual differential counting is often done by examining a stained blood smear and tallying about 100 white cells, while automated systems can classify cells as well. Absolute counts for each type can accompany the percentages, but this test’s primary purpose is the distribution of white cell types. The other tests focus on red blood cells or platelets—Mean Corpuscular Volume measures red cell size, Platelet Count counts platelets, and Hematocrit indicates the proportion of blood volume made up by red blood cells—so they do not describe the white cell composition.