Granulocytes are classified as neutrophils, eosinophils and basophils. Granulocytopenia usually refers to a decrease in neutrophils. Neutrophils are called granulocytopenia if they are less than 1.5 x 10^9/L. Granulocytopenia is often seen with infectious diseases such as influenza, measles, viral hepatitis, chickenpox, rubella, and cytomegalovirus, and these infections in patients can cause a decrease in granulocytes. In addition, granulocytopenia is often seen in aplastic anemia, granulocyte deficiency, or partial leukemia, and can occur in severe anemia. Radiation, chemicals, and some antibiotics, such as chloramphenicol, can also cause granulocytopenia. Granulocytopenia can also occur in cases of hypersplenism with excessive destruction of granulocytes.