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Learning About Low Blood Counts From Cancer Treatment

What are low blood counts?

Bone marrow is the soft tissue found mainly inside the long bones, vertebrae, and pelvic bones. The bone marrow's job is to make three important parts of your blood. These parts are:

  • Red blood cells, which carry oxygen from your lungs to the rest of your body.
  • White blood cells, which help your body fight infection.
  • Platelets, which help your blood clot.

When your bone marrow doesn't make new blood cells as it should, you have low blood counts. The medical term for this is bone marrow suppression.

The result of low blood counts will depend on which blood cells are affected.

  • A low level of red blood cells is called anemia. Without enough red blood cells, your body tissues get less oxygen, so you may feel weak and tired.
  • A low level of certain white blood cells (neutrophils) is called neutropenia (say "noo-truh-PEE-nee-uh"). These white blood cells help protect against infection. Without enough white blood cells, you are more likely to get infections.
  • A low level of platelets is called thrombocytopenia (say "throm-buh-sy-tuh-PEE-nee-uh"). Without enough platelets, your blood can't clot well. That means it's harder to stop bleeding.

Low blood counts are a common side effect of some cancer treatments. This usually starts about a week or two after treatment. If needed, your doctor will check your blood cell levels often.

Blood counts usually return to normal a few weeks after cancer treatment ends.

What are the symptoms?

The symptoms of low blood counts depend on which parts of the blood are affected.

Red blood cells

A low level of red blood cells may make you:

  • Feel weak and get tired more easily.
  • Feel dizzy or short of breath.
  • Have headaches.
  • Look very pale.
  • Have trouble concentrating.

White blood cells

A low level of white blood cells raises the risk of infection of your skin and organs. Signs of infection include:

  • A fever. Fever is a common symptom of infection. It may be the only symptom. If your white blood cell level is low and you develop a fever, call your doctor or nurse advice line right away.
  • A rash.
  • Diarrhea.
  • A cough or sore throat.
  • Pain or burning when you urinate.
  • Other problems such as:
    • Increased pain, swelling, warmth, or redness of your skin.
    • Red streaks leading from a wound.
    • Pus draining from a wound.


A low level of platelets may cause abnormal bleeding. Symptoms include:

  • Easy bruising.
  • Nosebleeds or bleeding gums.
  • Tiny red or purple spots on the skin.
  • Bloody or pink urine.
  • Bloody or black stools, or rectal bleeding.
  • Vaginal bleeding that is different (heavier, more frequent, at a different time of the month) than what you are used to.

Tell your doctor right away about any new or changing symptoms during your cancer treatment.

How are low blood counts treated?

You may get medicines and other treatments to help prevent problems from low blood counts.

  • For a low level of red blood cells, your doctor may prescribe a transfusion of packed red blood cells. This helps your blood carry more oxygen to the tissues of your body. Your doctor may also talk to you about using a medicine to help your body make more of its own red blood cells. These treatments can help you feel stronger.
  • For a low level of white blood cells, your doctor may prescribe antibiotics to help prevent infections. You may also take medicines to help your body make more white blood cells.
  • For a low level of platelets, you may not need treatment if it is mild. If you do need treatment, you may get a transfusion of platelets.

Your doctor may also recommend steps you can take at home to feel better and reduce your risk of infection and bleeding.

Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor or nurse advice line (811 in most provinces and territories) if you are having problems. It's also a good idea to know your test results and keep a list of the medicines you take.

Where can you learn more?

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