What is the normal range for a white blood cell count?

The normal range for a white blood cell count is commonly recognized as 4,500 to 11,000 cells per cubic millimeter (mm³) of blood. This range reflects the typical values found in healthy adults, with variations possible based on individual health factors, age, and laboratory standards.

White blood cells, or leukocytes, play a crucial role in the immune system, providing defense against infections and foreign substances. A count within this range indicates that the body is likely maintaining an effective immune response. Deviations from this range can suggest various medical conditions, such as infections, inflammatory diseases, or hematological disorders.

When considering the other options, they fall outside of the widely accepted normal range. For example, a count of 3,000 could suggest leukopenia, whereas counts above 11,000 may indicate leukocytosis, which may signify an active infection or other medical issues. Therefore, the choice of 4,500 to 11,000/mm³ for the normal white blood cell count aligns with standard clinical references and practices.