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

• Fever (see Fever, Fever)
• Glucocorticoids (see Corticosteroids, Corticosteroids)
• Infection: bacterial, viral

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

References

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