Health Library
Blood Counts, Understanding

What are Blood Counts?

Blood is the red fluid that goes to all parts of the body through the veins and arteries. Oxygen and nourishment are carried by the blood to all body cells. Blood is made in the bone marrow (a soft spongy tissue within our bones). Whole blood is made up of red blood cells, white blood cells, platelets and clotting factors, as well as liquid called plasma. Various substances, such as proteins, salts and sugar, are also carried within the plasma.

Children who receive chemotherapy or whose disease affects the bone marrow may have many changes in blood counts. When your child receives chemotherapy, the blood counts will be checked often.

Red Blood Cells (RBC)

RBCs contain hemoglobin, which carries oxygen to the body tissues and provides the red color of blood. A normal hemoglobin is 12 or greater. When the hemoglobin level is low, a child may become pale and tire easily, and his heart rate and respiratory rate may increase, because of a lack of oxygen. If your child's hemoglobin is very low, he may receive a red blood cell transfusion.


Platelets work to make clots to help stop bleeding if a blood vessel is cut or injured. A normal platelet count is 150,000 to 450,000.

When the platelet count is low, your child can bleed easily. A child with low platelet counts may bruise easily or have a bloody nose frequently. Blood in the stool and urine are less common.

If your child has a severe physical injury, and her platelet count is low, she may bleed uncontrollably. A severe headache in a child with low platelets may be a sign of bleeding in the head and needs emergency treatment.

When your child has a very low platelet count, she should avoid contact sports or any play that could cause physical injury. If your child has a nosebleed, pinch her nostrils tightly with constant pressure for at least 10 minutes while she is in a sitting position. No aspirin or ibuprofen products should be given, since they affect how platelets work in the body.

Brushing of the teeth with a soft bristle brush or sponge will help avoid unnecessary gum irritation. Other obvious bleeding should be treated first with direct pressure. If the bleeding does not stop, the physician should be notified right away. Your child may require a transfusion of platelets.

White Blood Cells (WBC)

White blood cells help us fight bacterial, fungal, viral and parasitic infections (germs). There are many different types of white blood cells, including neutrophils, eosinophils, basophils, monocytes and lymphocytes. Neutrophils, sometimes called granulocytes, kill and eat bacteria. The monocytes also fight any type of infectious agent.

There are two types of lymphocytes: B-lymphocytes and T-lymphocytes which help fight viral infections and coordinate the immune system.

A normal WBC is 5,000 to 10,000.

Absolute Neutrophil Count (ANC)

The absolute neutrophil count (ANC) is the total number of neutrophils (segmented neutrophils plus band forms of neutrophils) your child has to fight a bacterial or fungal infection. A normal ANC is greater than 1,500. And a low ANC is called neutropenia.

To find out what your child's ANC value is, simply add the percentage of segs plus the percentage of bands and multiply the number by the WBC count. For example, if your child's WBC is 4,000 and he has 20 percent segs and 10 percent bands:

Multiply the WBC number by the percentage or decimal:

20% segs 4,000 WBC
+10% bands x.30 neutrophils
30% (or .30) total neutrophils 1,200 ANC

Your child's ANC would be 1,200.

Sometimes when your child's ANC is low, it may be necessary to avoid some activities. You will need to watch for a rise in your child's temperature and call the oncology service when it is over 100.4 degrees Fahrenheit or higher.

In some cases when the ANC remains very low, a medicine known as Granulocyte-Colony Stimulating Factor, or G-CSF, may be given to help the ANC count to rise. This medication is given to stimulate the bone marrow to produce more neutrophils. Initially, chemotherapy and/or radiation, may cause your child's ANC to drop as low as zero.

If your child is in the hospital and his ANC is less than 500, he will be placed in protective isolation. This is to protect him from being exposed to possible infections. (However, most of the infections children get are caused by normal bacteria and fungi that live in or on your child's body.) Protective isolation means your child will have a private room and the door will remain closed. People will need to wash their hands as they go into or out of the room. People with colds or the flu will not be able to visit your child.

After chemotherapy, radiation, or bone marrow transplant, your child's ANC will slowly increase, showing the bone marrow is recovering and immune function is returning.


It is important for you to check your child's temperature if her body feels warm or if she does not feel well. Digital thermometers are acceptable. When taking a temperature by mouth, your child must keep the thermometer under her tongue with his lips closed.

Do not give your child any cold or hot drinks 30 minutes before you take her temperature, because this will alter the result you obtain. You can also put the thermometer under the child's arm. Hold that arm close to the body. When you report the actual reading to your child's physician, tell him or her the method (armpit, mouth) you used to take the temperature.

You should not check your child's temperature rectally. This can result in rectal tears, bleeding, or infections.

Follow the manufacturers' directions when taking your child's temperature. Tell the nurse if you do not have a thermometer at home or if you need help reading the thermometer.


When your child's ANC is low he may not be allowed to attend school. You may want to stay away from large crowds of people (e.g., church, shopping centers). Please check with your child's care providers about appropriate activities when your child's blood counts are low. Always avoid contact with individuals who are ill.

Emotional Care

When some of your child's activities are restricted she may be upset. In simple terms for her age, explain why this is necessary. Your child may need some extra attention and support from her family during these times.


No medication should be given to your child unless it has been approved by the oncology care team.


You should call your physician, nurse or the oncologist on call immediately if your child has:

  • A single temperature greater than or equal to 100.4 degrees Fahrenheit in a 12-hour period.
  • Cough
  • Pain in the rectal area
  • Other signs and symptoms of infection

If your child has not had chicken pox or the chicken pox vaccine and is around someone who has chicken pox, call your physician or nurse within 24 hours. Make sure your child's teacher and school nurse notify you if your child has been exposed to anyone in the class who has chicken pox or shingles. Call oncology at 513-517-2234 or call 513-636-4200 and ask for the oncologist on-call to be paged.


When your child's hemoglobin (Hgb) is low, it is called anemia. Anemia can be a side effect of chemotherapy or radiation. When your child is anemic he may tire easily or lack energy, feel weak, be irritable, look pale (especially around the lips and fingernails), have headaches and/or feel dizzy. In severe cases your child may breathe very quickly with small breaths or feel confused. You should call your child's physician or nurse when you notice signs and symptoms of anemia. Your child's physician will be checking your child's blood counts regularly.

If he is anemic, he may need a transfusion of red blood cells to increase his ability to deliver oxygen to the body tissues.

Vitamins with or without iron will not correct this type of anemia. Do not give vitamins or iron unless you discuss this with your child's physician.

Low Platelet Counts

A low platelet count (thrombocytopenia) can be the result of chemotherapy, radiation, or bone marrow disease. If your child has a low platelet count, you may see any of the following signs and symptoms:

  • Bleeding from the gums
  • Nosebleeds
  • Increased bruising
  • Dark, loose stools or blood in the stool
  • Blood in the urine (red or brown color)
  • Red / purple spots on the skin (petechiae)
  • Heavy menstrual periods
  • Headache

Your child's blood counts will be checked frequently while he is receiving cancer treatment. He may receive a platelet transfusion when his counts are too low or if he has bleeding problems.


Your child should avoid contact sports and activities such as biking, skateboarding, skating and wrestling when his platelet count is low. Your child's care team can tell you what activities should be avoided and what activities are safe.

Personal Care

When your child's platelet count is low, use a soft toothbrush or Toothette for brushing teeth to avoid gum bleeds.


Your child should avoid the use of drugs such as ibuprofen, aspirin, or aspirin-containing medications. The doctor may order stool softeners such as Colace and Senokot to prevent constipation and hard stools, which can cause small tears and bleeding in the soft tissue of the anal area.


Do not take rectal temperatures or give suppositories or enemas to your child. No intramuscular injections are to be given without asking your child's physician. If your child should have a nosebleed, apply pressure by pinching the nose for 10 minutes. If your child gets a cut, apply pressure over the cut for five minutes. Call your child's oncologist if the bleeding does not stop.


You should call your physician, nurse, or the oncologist on-call immediately when your child:

  • Has bright red blood in the stool or very dark, foul smelling stool
  • Continues to have a nosebleed after you have applied pressure for 10 minutes
  • Cuts herself and the bleeding does not stop after putting pressure over the site for five minutes
  • Has an increase in bruising, red spots on the skin, increase in menstrual flow or blood in urine
  • Complains of a severe headache, sudden vomiting or change in level of alertness

Blood Cell Markers Chart

Hemoglobin (Hgb)

Job of Blood Cell Carry oxygen to provide energy
Normal Count 12 or more
Low, But Probably OK 8-12
Low and Needs Attention Less than 7 (8 when your child is getting radiation therapy with sedation)
Signs of Low Count Pale, tired, irritable
Hospital and Home Transfusion of red blood cells. Provide rest, balanced diet.


Job of Blood Cell Make clots to prevent bleeding
Normal Count 150,000 - 450,000
Low, But Probably OK 50,000 - 100,000
Low and Needs Attention Less than 10,000 - 50,000
Signs of Low Count Bruising, bleeding
Hospital and Home Transfusion of platelets. Safe play.

Absolute Neutrophil Count (ANC)

Job of Blood Cell Fight infections
Normal Count 1,500 or more
Low, But Probably OK 500 - 1,000
Low and Needs Attention Less than 500
Hospital and Home Treat infections with IV antibiotics, protective isolation, perform good washing, avoid crowds and report fever or chicken pox exposure

Last Updated 12/2019