Low White Blood Cell Count (Neutropenia)

White blood cells fight infection. A normal white blood cell count is between 5,000 and 10,000 cells. A white blood cell count below 1,000 cells increases the risk of infection. In some cases, your child may be given a medicine, such as “G-CSF (granulocyte-colony stimulating factor),” to help increase the number of white blood cells in the bone marrow.


Different types of white blood cells have different jobs. The “differential” is part of the blood count report that shows the breakdown of the various types of white blood cells in your child’s blood count.

Neutrophils help to fight bacterial infections.

Lymphocytes make antibodies to fight infections.

Monocytes help to fight infection by killing and removing bacteria.

Basophils and eosinophils respond during an allergic reaction.

The term “ANC,” which stands for “Absolute Neutrophil Count,” is the total number of neutrophils in your child’s white blood cell count. We often refer to the ANC as the “infection-fighting” count. The lower the ANC drops, the higher the risk of infection. When the ANC drops below 500, the risk of infection is high.

ANC Value

Risk for Infection

Lower than 500


500 to 1,000


More than 1,000


On most blood count reports, you will see the ANC already calculated for you. You can also ask your health care provider to tell you the ANC. To calculate the ANC yourself, use this formula:

ANC = (% segs + % bands) x WBC

Look at your child’s differential. Add the percentage of segs (sometimes called polys or PMNs) and bands together (combined, these make up the neutrophil count). Multiply the neutrophil count by the white blood cell count (WBC).

Example: WBC = 1,000 % segs = 20 % % bands = 1%

ANC = (% segs + % bands) x WBC

ANC = (20% + 1%) x 1,000

ANC = (0.21 x 1,000)

ANC = 210 (high risk for infection)

Signs of Infection

While there are no outward signs of a low white blood cell count, it's important to be aware of the timing of low blood counts following chemotherapy. Whenever your child receives chemotherapy, you’ll want to speak with the nurse about the timing of low counts.)

Call your health care provider right away if you notice any signs of infection, including:
  • Fever
  • Chills
  • Cough
  • Trouble breathing
  • Diarrhea
  • Pain
If your child has a central venous access device (central line or port), check for redness, swelling, pain or pus at the site. A child with a low ANC may not have redness or pus, but could still have an infection.

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