What Do High Granulocyte Levels Mean?

Granulocytes are a family of specialized white blood cells—neutrophils, basophils, and eosinophils—that are produced in the bone marrow. High granulocyte levels—also known as granulocytosis—occur when there are elevated levels of these cells in the bloodstream.

Granulocyte levels are evaluated using blood work and laboratory tests such as a complete blood count (CBC). If your granulocyte levels are high, this may be an indicator of one of several processes including:

• Infection (bacterial, fungal, or viral)
• Allergic reaction
• Asthmatic reaction
• Inflammation
• Blood cancers such as chronic myelogenous leukemia
• Myelofibrosis (rare bone cancer that interferes with normal blood cell production)

What Are the Functions of Granulocytes?

Granulocytes are white blood cells that play a critical role in managing the immune system. They are the first cells to respond to an infection and can play a critical role in mediating allergies.

Each granulocyte has a specialized function within the body. This includes:

• Neutrophils: These are responsible for the initial response and line of defense against infection. Neutrophils respond to sources of infection within the body. They also can move and localize to a site of infection and eliminate bacteria, viruses, fungi, and parasites causing harm. Neutrophils are the most abundant cell identified at the site of infection and make up the majority of a person’s granulocyte level. Neutrophil levels can be specifically counted and are tracked during the course of an infection.
• Basophils: These help with responding to allergies and inflammation within the body. They play a critical role in recruiting other immune cells to the source of an allergy. Basophils cause inflammation through the release of histamine molecules and other chemical messengers that signal immune cells to respond. In response to an allergen, the basophil may cause an overactive immune response that can be life-threatening known as anaphylaxis. Basophil levels can also be abnormally elevated in a condition known as chronic myeloid leukemia. 
• Eosinophils: Eosinophils are responsible for managing chronic inflammation and parasitic infections within the body. They can be involved in the response of the body to allergies, cancer, and parasitic infections. Eosinophils are one of the primary cells involved in removing parasites from the body.

What Do High Granulocyte Levels Indicate?

Granulocyte levels are often high when the immune system is activated.

The immune system can be activated to fight infections that are:

• Viral
• Bacterial
• Fungal
• Parasitic

In addition, since granulocytes are involved in allergic reactions, they can be elevated in the presence of an allergic reaction to:

• A medication
• Bee sting
• Another substance

Also, since the bone marrow is where granulocytes are produced, if there is cancer in the bone marrow—such as with chronic myelogenous leukemia—then granulocyte levels may be abnormally elevated.

Other conditions that can cause elevated levels of granulocytes include:

• Polycythemia vera
• Primary myelofibrosis 
  

Treatments for High Granulocytes

There are many treatments available for high granulocyte levels.

Identifying the appropriate treatment depends on identifying the cause of the rise in granulocytes. For example:

• Infections may be treated with antibiotics.
• Allergic reactions may be treated with allergy medications and steroids.
• Cancer may be treated with chemotherapy, radiation, and bone marrow transplants.

Summary

 A high level of granulocytes in the blood is called granulocytosis. Granulocytosis is important because it can indicate an infection, autoimmune disease, or blood cell cancer.

There are many treatment options available for elevated granulocyte levels, and the treatments used depend on the underlying cause.

A Word From Verywell

A high granulocyte level may be one of the earliest signs of illness. It is normal to feel confused by the many causes of high granulocytes. More specific tests can be used to evaluate and determine the specific cause, and your healthcare provider can then recommend appropriate treatments.