A high white blood cell (WBC) count, also known as leukocytosis, generally means that your body is responding to some form of stress, infection, or inflammation. White blood cells are crucial components of the immune system, produced in the bone marrow, and they help fight infections and other diseases. When their count is elevated, it usually indicates that the body is actively fighting off an infection or dealing with inflammation

. Common causes of a high WBC count include:

• Infections (bacterial, viral, fungal, or parasitic)
• Inflammatory diseases such as rheumatoid arthritis or inflammatory bowel disease
• Allergic reactions, including asthma
• Physical or emotional stress
• Tissue damage from burns, injury, or surgery
• Certain medications like corticosteroids
• Pregnancy, which naturally raises WBC levels during the trimesters
• Smoking and obesity
• Some cancers, including leukemia and lymphoma, or bone marrow disorders

A WBC count above about 11,000 cells per microliter of blood is generally considered high, though exact reference ranges may vary by lab

. While a high WBC count often reflects a normal immune response, it can sometimes signal more serious conditions such as blood cancers or bone marrow diseases. Therefore, if the elevation is significant, persistent, or accompanied by symptoms like high fever, severe pain, or unusual bleeding, further medical evaluation is necessary

. In summary, a high WBC count means your immune system is active, most commonly due to infection or inflammation, but it can also indicate other medical conditions requiring attention.