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Basophils, which constitute a small percentage of the total leukocyte count, are considered phagocytic. The basophilic granules contain heparin, histamine, and serotonin. Tissue basophils are called mast cells and are similar to blood basophils. Normally, mast cells are not found in peripheral blood and are rarely seen in healthy bone marrow. Basophil counts are used to evaluate chronic inflammation. There is a positive correlation between high basophil counts and high concentrations of blood histamine, although this correlation does not imply cause and effect.


Normal reference values in adults


* Absolute basophil count: 15 to 50/mm3 or 0.02 to 0.05 x 109/L


* Differential: 0% to 1.0% of total white blood cells.


Possible causes of basophilia

(increased count) greater than 50/mm3 or greater than 0.05 x 109/L


* granulocytic (myelocytic) leukemia


* acute basophilic leukemia


* myeloid metaplasia, myeloproliferative disorders


* Hodgkin disease


* less commonly associated with:


* inflammation, allergy, or sinusitis


* polycythemia vera


* chronic hemolytic anemia


* splenectomy


* ionizing radiation


* hypothyroidism


* infections, including tuberculosis, smallpox, chickenpox, influenza


* foreign protein injection.



Possible causes of basopenia

(decreased count) <15/mm3 or <0.02 x 109/L


* acute infection


* hyperthyroidism


* stress reactions (such as pregnancy, myocardial infarction)


* prolonged steroid therapy, chemotherapy, radiation


* hereditary absence of basophils.



Interfering factors

False-positive values may be caused by:


* desipramine


* paroxetine


* tretinoin


* triazolam


* venlafaxine.



False-negative values may be caused by:


* procainamide


* thiopental.



Source: Fischbach FT, Fischbach MA. A Manual of Laboratory and Diagnostic Tests. 10th ed. Philadelphia, PA: Wolters Kluwer; 2018.