What Is the Acceptable Range for Eosinophils?

Eosinophil granulocytes, often calledeosinophils, are leukocytes and one of the five types of white blood cells. Like other white blood cells, they are responsible for battling foreign materials that invade the body including infectious bacteria and parasites. A high level of eosinophils, usually over 500 eosinophil cells per micro liter of blood, can indicate an infection, parasitic pest or even an allergy. Consult a doctor at any sign of infection, allergy or parasitic infestation.

Eosinophils Occurence

Eosinophils can occur either in the blood or in tissue. Blood eosinophilia occurs when a high level of eosinophil cells are present in the blood stream. Tissue eosinophilia usually occurs at the site of an infection.


Light Red Blood Streaks in Phlegm

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Blood drawn for standard blood tests can be tested for blood eosinophilia. Samples from exploratory surgeries can be tested, as well as mucus and other fluids from the nasal passages. People testing positive for tissue eosinophilia generally do not have blood eosinophilia, according to the Mayo Clinic. Tissue eosinophilia is diagnosed with a biopsy of the relevant tissue.

Normal Blood Ranges

The normal range for eosinophil is less than 500 eosinophils per micro liter of blood, according to the Mayo Clinic. Anything above that level is considered abnormal and indicates a diagnosis of blood eosinophilia.

Causes of Eosinophilia

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Diseases such as asthma, Crohn’s and lupus can cause eosinophilia. Trichinosis, a parasite associated with undercooked pork, and Ascariasis, a common roundworm, are typical parasitic infections that can cause eosinophilia. Allergies can also cause eosinophilia.


Eosinophilia is a symptom associated with other conditions. Treatment for the primary condition that caused the eosinophilia should result in the clearing of the eosinophilia.