Final answer:
A Differential White Blood Cell Count is a lab test used to assess the percentage of each type of white blood cells in the blood, differentiating granulocytes and agranulocytes with Wright-Giemsa stain, which can help indicate the presence of diseases such as infections.
Step-by-step explanation:
Differential White Blood Cell Count
To determine the percentage of each type of white blood cells, a lab test known as a Differential White Blood Cell Count or simply a "Diff" is used. This test involves making a blood smear, which is then stained using Wright-Giemsa stain to differentiate the types of leukocytes. White blood cells, which include granulocytes such as neutrophils, eosinophils, and basophils, as well as agranulocytes such as lymphocytes and monocytes, are crucial components of the immune system. By scanning the smear and tallying each cell type until a total of 100 cells is reached, medical professionals can determine the relative percentage of each white blood cell type.
These percentages are significant as they can indicate the presence of disease if they deviate from established normal values. For instance, an increase in neutrophils, or neutrophilia, often suggests an infection. The normal range of white blood cells is approximately 1,000 to 11,000 cells per microliter of blood, with healthy absolute numbers ranging from 3.5 to 11 x 109 cells/L. A differential count not only provides the percentage of each white blood cell type but can also show the presence of immature neutrophils, commonly known as "bands," which could be indicative of an ongoing infection.