Management of Absolute Eosinophil Count of 8 cells/μL
This is Not Eosinophilia and Requires No Specific Workup
An absolute eosinophil count of 8 cells/μL is profoundly low and does not represent eosinophilia—this is essentially zero eosinophils and requires no investigation for eosinophilic disorders. Normal absolute eosinophil counts range from 50-500 cells/μL, and eosinophilia is defined as >500 cells/μL 1, 2, 3.
Understanding the Context
Eosinophilia thresholds are clearly defined: mild eosinophilia is 500-1,500 cells/μL, moderate is 1,500-5,000 cells/μL, and severe is >5,000 cells/μL 1, 2.
Your count of 8 cells/μL is more than 60-fold below the threshold for even mild eosinophilia and represents either eosinopenia (low eosinophils) or a near-complete absence of eosinophils 1.
Clinical Significance of Low Eosinophil Counts
Low eosinophil counts can occur with acute stress, corticosteroid use, or acute infections, but are generally not clinically concerning in asymptomatic patients 4.
No parasitic workup, allergy testing, or hematologic evaluation is indicated for this profoundly low count, as all guidelines focus on elevated counts as triggers for investigation 1, 4, 3.
When to Actually Investigate Eosinophils
Investigation becomes relevant only when the absolute eosinophil count exceeds 500 cells/μL, particularly with travel history to helminth-endemic regions 1.
Urgent evaluation is required only when eosinophilia is accompanied by end-organ damage symptoms (chest pain, dyspnea, altered mental status, peripheral neuropathy) or when counts exceed 5,000 cells/μL 1.
Persistent hypereosinophilia (≥1,500 cells/μL for >3 months) requires hematology referral after excluding infectious causes 1.
Common Pitfall to Avoid
Do not confuse the eosinophil percentage with the absolute count—a 1% eosinophil differential with a white blood cell count of 8,000 cells/μL would yield an absolute eosinophil count of 80 cells/μL (still normal), not 8 cells/μL 3.
If your laboratory report shows "8" under eosinophils, verify whether this represents 8 cells/μL (absolute) or 8% (relative)—the latter would require calculating the absolute count by multiplying by the total white blood cell count 3.