CBC Biomarker
Collection Type: Blood
Related System: CBC
Eosinophils are a type of white blood cell (granulocyte) involved in immune responses against parasites and in allergic inflammation. A CBC with differential measures their absolute number and percentage of total white cells. Elevated eosinophils (eosinophilia) can suggest allergic diseases (asthma, allergic rhinitis, atopic dermatitis), parasitic infections, certain drug reactions, autoimmune conditions, or specific hematologic disorders. Low eosinophil counts (eosinopenia) occur with acute stress, steroid use, or severe infection. Testing is indicated for symptoms such as unexplained rash, wheeze or breathing difficulty, recurrent fevers, gastrointestinal complaints after travel, or signs of systemic organ involvement. Counts can vary with age, pregnancy, medications (especially corticosteroids), and acute illness.
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Symptom Checker0.0-0.5 x10^9/L OR 0-500 cells/µL (1–4% of total WBC)
Q: What if eosinophils are high?
A: High eosinophils (eosinophilia) suggest allergic conditions (asthma, eczema), parasitic infections, drug reactions, autoimmune diseases, or rare blood disorders. Many people are asymptomatic; others have skin rashes, cough, wheeze, abdominal pain or organ inflammation. Doctor evaluation includes repeat blood counts and tests to find causes (stool tests, imaging, allergy or autoimmune workup). Treatment targets the underlying cause; severe cases may need corticosteroids or biologic therapies.
Q: What is the danger range for eosinophils?
A: Eosinophil counts normal range: 0–0.5×10^9/L (0–500/µL). Eosinophilia is mild at 0.5–1.5×10^9/L (500–1,500/µL), moderate 1.5–5.0×10^9/L (1,500–5,000/µL), and severe >5.0×10^9/L (>5,000/µL). Counts above 1.5×10^9/L raise concern for organ involvement; levels >5.0×10^9/L carry highest risk of tissue damage and require urgent evaluation. Symptoms may guide treatment.
Q: What do eosinophils in a blood test mean?
A: Eosinophils are a type of white blood cell that help fight parasites and drive allergic and asthma-related inflammation. A high eosinophil count (eosinophilia) can signal allergies, asthma, parasitic infection, drug reactions, some autoimmune conditions or certain cancers. A low count is usually not concerning and can follow steroid use or acute infection. Clinical assessment and further tests determine the cause.
Q: Is it better to have high or low eosinophils?
A: Neither extreme is “better” a normal eosinophil count is ideal. High eosinophils (eosinophilia) can signal allergies, asthma, parasitic infections, autoimmune disease or certain cancers and may cause organ damage. Low eosinophils (eosinopenia) often reflect acute infection, stress or steroid use and immune suppression. Abnormal results should be interpreted with symptoms and evaluated by a clinician.
Q: What cancers cause high eosinophils?
A: Certain cancers can cause high eosinophils (reactive/paraneoplastic eosinophilia). These include hematologic malignancies—Hodgkin and non‑Hodgkin lymphomas, some leukemias (including chronic eosinophilic leukemia and acute leukemias)—and various solid tumors, notably lung (especially adenocarcinoma), gastrointestinal cancers, ovarian and renal tumors. Eosinophilia may reflect tumor production of eosinophil‑stimulating cytokines and warrants evaluation for underlying malignancy.
Q: What foods increase eosinophils?
A: Foods that commonly raise eosinophil counts are allergenic items that provoke allergic or eosinophilic GI reactions: cow’s milk, eggs, wheat, soy, tree nuts, peanuts, fish and shellfish. Additionally, undercooked or contaminated meats, fish, or produce can cause parasitic infections that elevate eosinophils. Individual responses vary; diagnosis and testing by a clinician guide management.