What it is: An eosinophil count measures the number of eosinophils, a type of white blood cell involved in fighting parasites and allergic responses, typically as part of a CBC with differential.
Why it's ordered: Ordered alongside a CBC with differential to evaluate suspected allergic reactions, asthma, parasitic infections, or certain autoimmune and blood conditions.
What it detects: Eosinophils rise (eosinophilia) with parasitic infections, allergic conditions, certain skin disorders, and some cancers; they fall (eosinopenia) with acute stress, inflammation, or corticosteroid use.
Collection & prep: A standard blood draw from a vein in the arm, as part of a CBC with differential. No special preparation is needed.
Results:
High – eosinophilia; linked to allergies, parasitic infection, asthma, or certain other conditions
Normal – typically 1–4% of total white blood cells
Possible complications: Persistently high eosinophil counts can be a sign of an underlying condition needing further workup, such as a parasitic infection (which may prompt stool ova and parasite testing) or an eosinophilic disorder.
Statements made in the Clinical Manual have not been evaluated by the FDA. The products mentioned are not intended to diagnose, treat, cure or prevent any disease.
