The Oncology Patient and Blood Counts

What is a blood count?

The blood count, also called the CBC, measures the level of red blood cells, white blood cells, platelets and hemoglobin in your body. Blood cells are made inside your bone marrow. The bone marrow is the spongy center of some of the bones in your body. These bones include the skull, sternum (breastbone), pelvis and vertebrae (backbone).

Why do I need to have a CBC?

Some diseases can be diagnosed or watched by readings of your blood cell count. Some of the therapies that your doctor prescribes for your condition may also affect your blood cell count.

About Your Blood Cells

What are Red Blood Cells?

Also called RBC's, these cells carry oxygen to your body's tissues. Hemoglobin is a substance found inside your red blood cells.

Hemoglobin gives red blood cells their red color. Oxygen in your lungs from the air that you breathe attaches to the hemoglobin in the red blood cells. This oxygen is then carried to the tissues. Hemoglobin also takes away the carbon dioxide from the tissue to the lungs where it is then breathed out of your body.

Anemia is a disease of the red blood cells where there are not enough cells or hemoglobin to do the job that your body needs. This is why when you are anemic you are short of breath and feel very tired.

The normal level of red blood cells is 4-6.
The normal level of hemoglobin is 12-18.

What are White Blood Cells?

Also called WBC's, white blood cells fight infections in your body. You may also hear white blood cells called "leukocytes".

Neutrophils are one of the two basic kinds of white blood cells. Neutrophils are the front line of defense against infection by bacteria. You can think of them as soldiers that gobble up bacteria in your body. A little over half of your WBC's are neutrophils.

Lymphocytes are the other major kind of white blood cell. They produce antibodies that destroy infections.

The normal level of white blood cells is 4-11.

Neutropenia is a condition where the neutrophil in your body are very low and there may not be enough to fight off bacteria. This makes it easy for you to get infections. Some medicines like chemotherapy and also radiation therapy can drop your neutrophil count temporarily. Your doctor or nurse will tell you when you should be most aware and alert about protecting yourself against infection.

These signs of infection need to be called to your doctor or nurse right away:

  • A temperature higher than 100.5º
  • Shaking chills
  • Flushed skin
  • Sweating for no reason
  • Frequent urination or burning with urination
  • Redness, tenderness or pain anywhere on the body
  • Flu-like symptoms such as sore throat, sneezing, runny nose, cough, vomiting, diarrhea

What are platelets?

Platelets are the smallest cells in the blood. They clump together and plug up or clot when there is an injury to the body. They help to stop bleeding. Platelet levels can be too low or too high with some diseases. Some medicines, such as chemotherapy or radiation therapy can temporarily lower blood platelet levels. Medicines that have aspirin in them can cause platelets to not be able to clump together.

The normal platelet level is 150,000 to 350,000.

A low platelet level is called thrombocytopenia. If you have low platelets, you may bruise very easily. You may also notice:

  • Tiny, pinpoint-sized red or purple spots on your skin. These are called petechiae
  • Nose bleeds
  • Bleeding gums
  • Long time to stop cuts from bleeding
  • Black or bloody stools
  • Brown or red urine
  • Heavier menstrual flow

Your doctor or nurse will tell you when you need to make some changes to protect yourself against injury from having low platelets. Some things that you should try to do:

  • Do not take any medicine that has aspirin in it. There are many over the counter drugs that have aspirin in them. Ask your doctor, nurse or your pharmacist before taking any medicines to see if they have aspirin in them. They may also have a list to give to you of medicines to avoid.
  • Let your doctor or nurse know if you notice any of the symptoms of low platelets if they are not already aware
  • Do not floss
  • Brush your teeth very gently with a soft toothbrush
  • Do not walk around without shoes or slippers
  • Ask before doing any sports like skiing or hockey
  • Use common sense if you have to work with any sharp objects like knives
  • Ask if you should avoid tampons or enemas
  • Blow your nose gently

Reference: Patient Information Publications
Warren Grant Magnuson Clinical Center
National Institutes of Health

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