What is the typical normal range for an adult white blood cell count?

• A. 4,000-11,000 cells/µL
• B. 3,000-8,000 cells/µL
• C. 5,000-12,000 cells/µL
• D. 4,000-10,000 cells/µL

Answer: (A)

A typical adult white blood cell count falls in about 4,000 to 11,000 cells per microliter. This broad reference range reflects normal biological variation among individuals and minor lab-to-lab differences, and it covers common fluctuations due to factors like stress or mild infection. Counts within this span are considered normal, while values outside may prompt further evaluation. The range of 4,000–11,000 best matches the standard reference interval used in most clinical settings, making it the correct choice. Counts significantly lower or higher than this span would be interpreted as leukopenia or leukocytosis, respectively, rather than normal variation.