Your Blood Counts During Chemotherapy

Chemotherapy affects not only cancer cells but also healthy cells in your bone marrow, which make your blood cells. Because of this, your care team will monitor your blood counts regularly using a test called a Complete Blood Count (CBC). Keeping track of these numbers helps your provider make sure you are safe to continue treatment and helps prevent complications.

What Your Blood Counts Measure

White Blood Cells (WBCs) and Neutrophils

WBCs help your body fight infection. A type of WBC called a neutrophil is especially important. When this number drops too low (neutropenia), your body has a harder time fighting off bacteria, making infection more likely.

Red Blood Cells (RBCs) and Hemoglobin

RBCs carry oxygen throughout your body. Low levels (called anemia) can make you feel tired, weak, or short of breath because your tissues are not getting the oxygen they need.

Platelets

Platelets help your blood clot. Low platelet counts (thrombocytopenia) increase your risk of bruising, bleeding, or nosebleeds.

Symptoms of Low Blood Counts

Low Red Blood Cells (Anemia)

  • Fatigue
  • Dizziness or lightheadedness
  • Feeling unusually cold
  • Shortness of breath
  • Pale appearance

Low White Blood Cells (Neutropenia)

  • Fever
  • Frequent infections
  • Wounds or sores that don’t heal

Low Platelets (Thrombocytopenia)

  • Easy bruising
  • Bleeding gums
  • Nosebleeds

Why Monitoring Is Important

Monitoring your blood counts helps your care team:

  • Prevent serious complications such as infection, bleeding, or severe fatigue
  • Decide whether your treatment can safely continue as scheduled
  • Make adjustments to doses or timing when needed

How Low Blood Counts Are Managed

Your care team may recommend one or more of the following:

Growth factor injections

These medications help your bone marrow make more blood cells before levels become dangerously low.

Blood or platelet transfusions

Sometimes transfusions are needed to treat anemia or prevent bleeding when counts are very low.

Taking Extra Precautions

If your counts are low, you may need to:

  • Wash your hands frequently
  • Avoid crowded places or sick contacts
  • Use an electric razor to prevent cuts
  • Avoid aspirin or ibuprofen if your platelets are low