Complete Blood Count (CBC)

Eosinophil Count

Normal Localization of Eosinophils

  • Eosinophils are normally several hundred-fold more abundant in tissues than they are in the blood: they are recruited to the these organs by eotaxins (which bind to the eosinophil CCR3 receptor
  • Normal Anatomic Sites of Eosinophil Localization
    • Gastrointestinal Tract: except for the esophagus
    • Lymph Nodes
    • Mammary Glands
    • Spleen
    • Thymus
    • Uterus

Mechanisms Which Decrease the Eosinophil Count

Determination of Eosinophil Count

  • Utilizing the Percentage of Eosinophils: this is not recommended due to the fact that absolute neutrophils counts vary between ethnic groups –> this will significantly impact the percentage of eosinophils
    • Therefore, determination of the absolute eosinophil count is recommended
  • Determination of Absolute Eosinophil Count: multiply percentage of eosinophils x total WBC count
    • Normal Absolute Eosinophil Count: 0-500 eosinophils per uL (<0.5 x 10 to the ninth/L)
    • Note: blood eosinophil counts vary within the same patient (normal or with an eosinophilic disorder) throughout the day and on different days –> however, this fluctuation is usually not clinically significant


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