Your Complete Blood Count and Breast Cancer Treatment

Chemotherapy can lower your blood counts. A complete blood count (CBC) is a routine blood test done regularly during treatment for breast cancer. Ask for and keep a copy of each of your CBCs.


Understanding Your Complete Blood Count (CBC)

Chemotherapy patient
Simon Jarratt/Corbis/VCG/Getty Images

A sample of your blood will be drawn and tested to assess the different elements in your blood (described in detail later). The results of this test will show how well your vital organs are functioning, and how well the treatment is killing your cancer. A CBC will reveal such blood conditions as neutropenia, anemia, or thrombocytopenia. All of these conditions can be treated.

Five Measurements

Red Blood Cells (RBC) – Red blood cells contain hemoglobin, and carry oxygen throughout your body. These cells also remove waste products from your tissues. RBCs are measured in millions per cubic millimeter (mil/mm3) of blood.

White Blood Cells (WBC) – White blood cells are an important part of your immune system. There are many types of white blood cells, such as neutrophils. WBCs are measured in thousands per cubic milliliter (K/mm3) of blood.

Platelets (PLT)Platelets, also called thrombocytes, are very small fragments of cells about one-tenth the size of a red blood cell. Their main function is to form a clot to prevent prolonged bleeding. PLTs are measured in thousands per cubic millimeter (K/mm3) of blood.

Hemoglobin (HGB)Hemoglobin carries oxygen and gives red blood cells their color. When you inhale, hemoglobin carries oxygen from your lungs to your tissues, and when you exhale, hemoglobin passes carbon dioxide out of your body. HGB is measured in grams per deciliter (g/dL) of blood.

Hematocrit (HCT) – Hematocrit measures the percentage of red blood cells in relation to your total blood volume.

Normal Ranges for These Measurements:

RBC: 3.58-4.99 mil/mm3
WBC: 3.4-9.6 K/mm3
PLT: 162-380 K/mm3
HGB: 11.1-15.0 g/dL
HCT: 31.8-43.2%


White Blood Cell Levels and Neutropenia

White blood cells are important to your health because they fight infection. Unlike red blood cells, there are several different types of white blood cells.


  • Neutrophils (polys and bands) (NE)
  • Lymphocytes (LY)
  • Monocytes (MO)
  • Eosinophils (EO)
  • Basophils (BA)

Each of these types of white blood cells will be measured and reported on your CBC as a percent and as a number.

Your Absolute Neutrophil Count (ANC)

Neutrophils, also called granulocytes, make up more than half of your total white blood cell count. There are two types of neutrophils: polys and bands, which must be counted separately. Your CBC report will have a number for ANC or AGC (Absolute Granulocyte Count). This is an important number because it shows how well your body can fight off an infection. A normal neutrophil count is 2,500 to 6,000. Your ANC is calculated by this formula:

White blood cell count x (number of polys + number of bands) = Absolute Neutrophil Count


If your neutrophil count is less than 1,000, you have an increased risk of infection. If your absolute neutrophil count (ANC) drops below 1,000, you could easily get a serious infection. This condition is called neutropenia and can be treated with injections of Neulasta or Neupogen (filgrastim). Labs vary on their ranges, but mild neutropenia would be an ANC of 1,000 to 1,500, moderate would be an ANC of 500 to 1,000, and severe an ANC of fewer than 500. If you get an infection, it must be treated with antibiotics. In extreme cases, a bone marrow transplant can be given.

Note that African Americans and southeast Asians have normal ANCs in lower ranges and that a diagnosis of neutropenia would also occur at a lower number.


Red Blood Cells and Anemia, Platelets, and Thrombocytopenia

If your red blood cell count is below normal, you are anemic. During anemia, your hematocrit and hemoglobin levels will also be low, so your blood oxygen levels will be low, meaning you’ll have too much carbon dioxide in your body. Anemia leads to fatigue, weakness, dizziness, trouble getting a full breath, headache, and ringing in the ears. This condition can be treated with injections of Procrit or darbepoetin. Low levels of hematocrit and hemoglobin may require a blood transfusion.

Platelets Count and Thrombocytopenia

If your platelet count is low, your blood may not able to clot. This condition is called thrombocytopenia. If you got cut or if a blood vessel broke, your platelets could not seal the break, and you might experience a hemorrhage. Thrombocytopenia can lead to nosebleeds, bruises that heal slowly, bleeding gums, red or brown urine, bloody stool, and vaginal bleeding (not menstrual). This condition can be treated with drugs that boost platelet production, or a platelet transfusion may be needed.​​

Was this page helpful?

Article Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial policy to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  • National Institutes of Health. NIH Clinical Center. Patient Information Publications. Complete Blood Count. PDF file, published April 2000.