A decrease in the number of circulating neutrophils (both segmented and band forms), strictly defined as an absolute total neutrophil count (ANC) of <1,500/μL in children >1 year of age, <1,000/μL in children <1 year of age, and <5,000/μL in the 1st week of life

  • To calculate ANC, multiply the total WBC count by the percentage of segmented neutrophils and band forms.
  • For example: WBC count 5,200/μL with 15% segs/polys, 4% bands, 76% lymphocytes, 5% monocytes: ANC = 5,200 × (0.15 + 0.04) = 988
  • Severe neutropenia is defined as an ANC <500/μL.


  • Normal values for total WBC counts and ANC vary with age and race.
    • Children of some ethnic groups, including African and Middle Eastern groups, have lower total WBC counts and lower ANCs than do Caucasian children.
    • Lower end of normal range for ANC may be 800/μL in 30% of African Americans and does not represent an increased risk for infection.
  • Infants have a higher total WBC count and a higher percentage of lymphocytes in their differential counts.
  • Prevalence of congenital and idiopathic neutropenia: 2.1 cases per million in the United States
  • Incidence of neonatal alloimmune neutropenia: 2 per 1,000 live births

Risk Factors


  • A number of mutations causing severe congenital neutropenia have been identified.
    • Autosomal recessive: HAX1 (Kostmann syndrome), G6PC3, SBDS (Shwachman-Diamond syndrome), others
    • Autosomal dominant: ELANE, GFL1, GATA2, others
    • X-linked: WASP, TAZ (Barth syndrome), others
  • Cyclic neutropenia: autosomal dominant or sporadic (ELANE)


Decreased phagocytic activity due to decreased numbers of neutrophils


  • Decreased production of neutrophils
    • Viral suppression
    • Marrow suppression by drugs, chemotherapy, or radiation
    • Nutritional deficiencies
    • Primary disorders of myelopoiesis
  • Increased destruction of neutrophils
    • Immune-mediated destruction
    • Increased use (usually with overwhelming infection)
    • Sequestration in the spleen

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