University of Chicago: Fever and Neutropenia in the Non-Chemotherapy Patient

Laboratory errors may occur in the initial diagnosis of neutropenia, and as such significant neutropenia must be confirmed by repeating the CBC with differential & platelets in order to avoid an extensive evaluation due a laboratory error.

Once confirmed, neutropenia is defined as an absolute neutrophil count (ANC) <1500 cells/microL. The ANC is calculated using the following formula:

ANC = total white blood cell count (cells/microL) x (percent neutrophils + percent bands) ÷ 100

Normal values for the ANC vary by age, particularly during the first weeks after birth.  See Reference number 1 by Segel et al or click here for a reference table of normal leukocyte counts by age.

In general, for patients older than 1 year of age, neutropenia is defined as:

  • Mild – ANC 1,000 to 1,500/mcL
  • Moderate –  ANC 500 to 1,000/mcL
  • Severe  –  ANC less than 500/mcL

In general, there is little or no heightened infectious risk if the ANC isgreater than 1,000/mcL.


There are various acquired and inherited etiologies that can account for fever and non-chemotherapy-induced neutropenia in children.  In general, the acquired neutropenias are considered first because they are most common.

The most common underlying etiology for mild-to-moderate neutropenia is transient marrow suppression due to a variety of viral infections.

The table below is from Segel et al and it highlights the causes of aquired neutropenia in children:

Ariana-Leilani is being denied Severe Neutropenia (ANC<500) life-saving medicine “Neupogen”… Please sign her petition:


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