Blood counts and blood and marrow transplant

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Learn why blood counts are important after your child's blood and marrow transplant.

Key points

  • A complete blood count will be done daily to measure the number of white blood cells, neutrophils, platelets and hemoglobin in your child's blood.
  • A complete blood count helps the health-care team monitor how well your child is responding to the transplant.

The blood and marrow transplant (BMT) will destroy most of the marrow cells in your child’s bone marrow. We need to check how well your child’s body is making new blood cells. Counting the number of blood cells is a helpful way to monitor how well your child is responding to the transplant. For this reason, your child’s nurse draws blood from your child daily.

The complete blood count test measures:

Total number of white blood cells

White blood cells fight infection and defend our body against disease. There are many different types of white blood cells. These include:

  • neutrophils (or Polys) and monocytes, which engulf bacteria or fungi in our body to fight infection
  • eosinophils and basophils, which respond to allergic conditions
  • lymphocytes, which fight against infection. They are also found in the lymph nodes, spleen, and lymphatic channels

Generally, all white blood cells perform the same function — to fight off infection. This is why looking at the combination of white blood cells is a more meaningful way to assess your child’s progress.

A healthy amount of white blood cells for your child is between 4.5–11.0 billion cells/liter of blood.

Absolute neutrophil count (ANC)

In an ANC, doctors count the amount of a specific type of white blood cell, called neutrophils. These white blood cells are the first to show up at the site of an infection. Having a healthy number of neutrophils is important for a strong immune system.

A normal amount of neutrophils (polys) cells is in the range of 1.5–7.8 billion cells/liter of blood. For your child, safe values are generally having more than 0.5 billion polys/liter of blood.


Platelets help control bleeding at the site of a cut. They bind to the wound and stick to each other, plugging the wound to stop bleeding. Having too few platelets causes more bruising than usual.

A normal range of platelets in the blood are 150–400 billion cells/liter of blood. Generally a safe level is greater than 50 billion cells/liter. However, for a child that is being closely monitored, safe levels can be as low as 10 billion cells/litre.

Hemoglobin (Hgb)

Hemoglobin is a protein that carries oxygen in red blood cells. Doctors measure the amount of hemoglobin so they know the number of red blood cells transporting oxygen to the rest of the body.

A healthy hemoglobin count is within the range of 120–140 grams/liter of blood. A closely monitored child will be safe at lower hemoglobin values and generally will tolerate levels as low as 70 grams/liter.

Last updated: January 6th 2010