what is eosinophils in blood test

Eosinophils are a type of white blood cells that protect the body from parasites, allergens, foreign bacteria, and outside organisms. An absolute eosinophil count is a blood test that measures the number of eosinophils in the blood. The normal eosinophil count is less than 500 cells per microliter of blood. A higher-than-normal eosinophil count may indicate an allergic reaction, cancer, infection by a parasite, or early stages of Addison disease. A lower-than-normal eosinophil count may be due to alcohol intoxication or overproduction of certain steroids in the body. The test cannot tell if the higher number of cells is caused by allergy or parasite infection.