What is a differential leukocyte count?

A differential leukocyte count specifically measures the percentage of each type of white blood cell (leukocyte) present in a blood sample. This test is essential for diagnosing various medical conditions, such as infections, allergies, and leukemias, as the relative numbers of different leukocyte types can provide valuable insights into the body’s immune response and overall health.

For instance, an increase in neutrophils may indicate a bacterial infection, while elevated eosinophils could suggest an allergic reaction or parasitic infection. The process typically involves staining a blood smear and counting the types of cells under a microscope, allowing for detailed analysis and interpretation of the immune status of an individual.

In contrast, the other options describe different aspects related to blood analysis but do not pertain to the differential leukocyte count. For example, measuring the total number of red blood cells is completely separate from evaluating white blood cell percentages. Blood clotting factors pertain to hemostasis and are measured through different tests, while collecting blood from a vein refers to the method of obtaining a sample for laboratory analysis rather than analyzing the components of that sample.