White blood cells are classified into 5 categories: neutrophils, lymphocytes, monocytes, eosinophils, and basophils. The white blood cell count (WBC) refers to the total number of white blood cells in the blood, and the white blood cell classification refers to the percentage of each type of cell obtained by sorting and counting. Different diseases can trigger changes in the number of different types of white blood cells. Clinicians can determine the cause of a disease by the number or percentage of white blood cells. Normal adult WBC total count is (4.0 to 10) × 10/L; classification percentage: neutrophils (NEUT) 45% to 70%, lymphocytes (LYM) 20% to 40%, monocytes (MONO) 3% to 8%, eosinophils (EO) 0.5% to 5%, and basophils (BASO) 0 to 1%. Once the body is judged to be infected, the leukocyte classification can be used to determine what type of infection is present and thus what type of medication to use.
Lymphocyte count, 20% to 40% of total white blood cells. Increases are seen in pertussis, infectious mononucleosis, viral infections, acute infectious lymphocytosis, and lymphocytic leukemia; lymphocyte ratios are relatively elevated in neutropenia, and some leukemias can also be associated with elevated eosinophils.