What is Granulocyte?

Granulocytes, or granular leukocytes, are white blood cells found in the bloodstream. They’re an important component of the human immune system, helping the body fight infection. Granulocytes are a type of polymorphonuclear leukocyte and are part of the innate immune system.


Granulocytes are found in the blood and help fight infection. They are one of the body’s main defenses against bacteria, viruses, and other foreign substances. Granulocytes also help rid the body of dead cells and cellular debris.


Granulocytes are not typically collected by a healthcare provider like other blood cells, since they are found naturally in the bloodstream. However, they can be collected for testing or analysis and stored in a sample container.

Types and Characteristics

Granulocytes can be divided into three types: neutrophils, eosinophils, and basophils. Each type of granulocyte has different morphological and functional characteristics.

  • Neutrophils: These are the most common granulocytes and are responsible for destroying and digesting bacteria, viruses, and other foreign bodies.
  • Eosinophils: These granulocytes are responsible for mediating inflammation and the immune response to allergens.
  • Basophils: These granulocytes release histamine and cytokines that cause vasodilation, which increases the circulation of other immune cells.


Granulocytes are considered healthy when the levels of each type are within a normal range. If the levels are too high or too low, it can indicate an underlying health problem and should be evaluated by a doctor. Low levels of granulocytes can be a sign of anemia, infection, or autoimmune disease. High levels can indicate an allergic reaction, leukemia, or other blood disorders.

When to See a Doctor

It’s important to talk to a doctor if you have any concerns or experience any symptoms that may be related to abnormal granulocyte levels. A doctor can order blood tests to measure the levels of granulocytes in the bloodstream and diagnose any medical conditions. Treatment may include medications, dietary changes, or lifestyle adjustments, depending on the underlying condition.