### Neutrophils: Key Players in Your Immune System Neutrophils are a type of white blood cell that play a crucial role in your immune system. They are the most abundant type of white blood cells, making up 50% to 75% of them. These cells are produced in the bone marrow and have a short lifespan of less than a day, so your body constantly makes new ones. #### Function The primary function of neutrophils is to fight infections and help heal wounds. They travel to the site of infection and ingest or break down bacteria, viruses, and fungi. Neutrophils work alongside other immune cells to protect your body from harmful germs. #### Testing Neutrophil Levels Doctors often use a Complete Blood Count (CBC) test with differential to measure the number of each type of blood cell, including neutrophils. The Absolute Neutrophil Count (ANC) is part of this test and indicates the number of neutrophils in your blood. #### Normal and Abnormal Levels - **Normal Range**: 2,500 to 7,000 neutrophils per microliter. - **Low Count (Neutropenia)**: Less than 1,500 neutrophils per microliter. This can make you more susceptible to infections. - **High Count (Neutrophilia)**: More than 7,700 neutrophils per microliter. This can be caused by infections, inflammation, certain medications, or some types of cancer. #### Neutropenia Neutropenia can be mild, moderate, or severe. It can be congenital (present at birth) or acquired over time. Causes include certain infections, cancers, and medications. Symptoms are usually related to the increased risk of infections. #### Neutrophilia Neutrophilia is often caused by infections, inflammation, medications, or cancer. Symptoms depend on the underlying cause and may include signs of infection or inflammation. #### Treatment Treatment for abnormal neutrophil levels focuses on addressing the underlying cause. For neutropenia, this may include antibiotics for infections or medications to stimulate white blood cell production. For neutrophilia, treatment involves managing the condition causing the high neutrophil count. Understanding neutrophils and their role in your immune system can help you better manage your health, especially if you have conditions that affect your neutrophil levels.