Leukocytosis means you have a high white blood cell count. This means you have more white blood cells than normal. Leukocytosis is a normal immune response and isn’t always a cause for concern. …

Jun 11, 2005 · Learn the causes of this increase in disease-fighting cells in the blood.

Dec 2, 2025 · A high white blood cell count can be caused by an infection, cancer (rarely), and many other causes. Learn the symptoms and when to see a healthcare provider.

Jul 9, 2025 · A white blood cell (WBC) count above about 11 × 10⁹/L usually signals that your immune system is reacting to something—most often infection, inflammation, severe stress, certain …

There are many reasons why your white blood cell count may be high. Learn why yours may be higher than normal, the related symptoms, how to get a diagnosis, and treatment options.

What is a white blood count (WBC)? A white blood count measures the number of white blood cells (WBCs) in your blood. White blood cells, also called leukocytes, are part of your immune system. …

When your white blood cell count rises above the normal range—typically 4,000 to 11,000 cells per microliter—it’s called leukocytosis. This elevation often indicates that your body is responding to a …

High White Blood Cell Count - Learn about the causes, symptoms, diagnosis & treatment from the Merck Manuals - Medical Consumer Version.

A high white blood cell count, also called leukocytosis, is a common finding on routine blood tests. It often reflects your immune system responding to something simple or temporary, such as a recent …

Apr 21, 2024 · Leukocytosis, characterized by an elevation in the white blood cell count, is a common clinical finding with various potential causes, encompassing infections, inflammation, malignancies, …