From the Research
Normal White Blood Cell (WBC) Count
A normal WBC count can vary depending on several factors such as age, sex, and ethnicity.
- The median WBC count was found to be 6.3 (interquartile range 5.4-7.2) for men and 5.7 (4.9-6.8) for women in a study of 75-year-olds 1.
- Race-specific WBC reference intervals were established using data from the US National Health and Nutrition Examination Survey (NHANES) of 2000-2003, with the following 2.5-97.5 percentile WBC limits:
- Non-Hispanic black males (12-18 years): 3.2-9.3 × 10⁹/L
- Non-Hispanic black females (12-18 years): 3.7-10.1 × 10⁹/L
- Adult non-Hispanic black males: 3.1-9.9 × 10⁹/L
- Adult non-Hispanic black females: 3.4-11 × 10⁹/L 2.
- A normal WBC count is generally considered to be between 4,000-10,000/L, as seen in a study of febrile patients with normal WBC counts and high C-reactive protein levels 3.
- The full blood count, which includes the WBC count, is a key diagnostic tool for a range of conditions, including infection, leukaemia, and lymphoma 4.
Factors Affecting WBC Count
Several factors can affect WBC count, including:
- Age: WBC counts can vary with age, with higher counts typically seen in younger individuals 5.
- Sex: WBC counts can also vary between males and females, with higher counts typically seen in males 1.
- Ethnicity: WBC counts can vary between different ethnic groups, with non-Hispanic black individuals tend to have lower WBC counts than non-Hispanic white individuals 2.
- Infection: WBC counts can be elevated in response to infection, with higher counts indicating a greater immune response 5, 3.