Which statement about white blood cell counts is accurate?

• A. A count of 4,000/µL is above the normal range.
• B. A count of 4,000/µL is below the normal range.
• C. A count of 4,000/µL is within the normal range.
• D. White blood cell counts are not used clinically.

Answer: (C)

Understanding normal white blood cell counts helps interpret whether the immune system is functioning within the expected range. In adults, the typical normal range for white blood cells is about 4,000 to 11,000 per microliter (µL). A count of 4,000/µL sits at the lower end of that normal window, so it is considered within the normal range. Counts below this level can indicate leukopenia, while higher counts can indicate leukocytosis, both of which may reflect infection, inflammation, or bone marrow issues. White blood cell counts are routinely used in clinical practice as part of a complete blood count to assess immune status and guide diagnosis and treatment.