Neutrophils are a type of white blood cell that play a crucial role in your body's immune system by helping fight infections and heal injuries. They are the most common type of white blood cell, making up about 55% to 70% of all white blood cells in the body
. Neutrophils are produced in the bone marrow and circulate in the blood and tissues. When an infection or injury occurs, they are among the first immune cells to respond by migrating to the affected site, where they engulf and destroy bacteria, fungi, and other pathogens through a process called phagocytosis
. They also release substances that help kill microbes and signal other immune cells to assist in the response
. In a blood test, the number of neutrophils is measured to assess immune function and detect infections, inflammation, or other conditions such as leukemia. This measurement is often reported as the absolute neutrophil count (ANC), which indicates the exact number of neutrophils per microliter of blood. Normal ANC values typically range from about 2,500 to 7,000 neutrophils per microliter in healthy adults; values outside this range may indicate a health issue
. Low neutrophil counts (neutropenia) increase the risk of infections, while high counts (neutrophilia) may indicate infection, inflammation, or other stressors on the body
. Blood tests like the complete blood count (CBC) with differential include neutrophil counts to help diagnose and monitor these conditions
. In summary, neutrophils are essential white blood cells that protect the body by fighting infections and aiding tissue repair, and their levels in a blood test provide important information about immune health and potential underlying conditions.
