What this marker measures
Eosinophils normally represent only 1–4% of white blood cells. A dramatic rise may prompt testing for parasitic infections or certain rare conditions.
High or low: what it can mean
High Eosinophils
Elevated eosinophils (eosinophilia) are most commonly associated with allergic conditions such as asthma, eczema, or hay fever, and with intestinal parasites. Many causes are benign and manageable.
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Low Eosinophils
Low eosinophils are generally not clinically significant and can be a normal finding, particularly during acute infections when neutrophils dominate.
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Frequently asked questions
What is Eosinophils?
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Eosinophils are white blood cells that play a role in allergic reactions and defending against parasitic infections.
What does Eosinophils measure?
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Eosinophils normally represent only 1–4% of white blood cells. A dramatic rise may prompt testing for parasitic infections or certain rare conditions.
What does high Eosinophils mean?
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Elevated eosinophils (eosinophilia) are most commonly associated with allergic conditions such as asthma, eczema, or hay fever, and with intestinal parasites. Many causes are benign and manageable.
What does low Eosinophils mean?
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Low eosinophils are generally not clinically significant and can be a normal finding, particularly during acute infections when neutrophils dominate.
Related biomarkers
Editorial note
LabTestly explains lab markers using plain-English educational content. Reference ranges may vary by laboratory and should be interpreted with a clinician.
Educational content · Editorially reviewed for clarity · Last updated
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Not medical advice
This page is for general understanding only and does not replace medical advice from your clinician. Reference ranges can vary by laboratory, age, sex, pregnancy status, medications, and clinical context.