PDF download is not available for Arabic and Urdu languages at this time. Please use the browser print function instead

Learn about blood work. It involves an amount of blood being drawn from a child to analyze the effect of drugs and checking things such as hemoglobin.

Key points

  • Blood work can be done in a variety of ways: ranging from a finger prick to having blood drawn with a needle at a blood work clinic.
  • The most common blood test is the complete blood count (CBC), which measures red and white blood cells, platelets, and hemoglobin.
  • Checking hemoglobin is important to ensure your child does not have anemia (iron deficiency).

Your child may need blood work at any stage, from diagnosis to before surgery, and throughout treatment. Blood work is also used to monitor the effect of drugs.

The complete blood count (CBC) is the most common blood test. It measures the amount of red blood cells, white blood cells, platelets, and hemoglobin in the blood.

Checking hemoglobin is important, especially in children who have low blood oxygen levels. Low hemoglobin is a sign of anemia, which is an iron deficiency. Anemia occurs when there are not enough red blood cells in the body, which means the heart must work harder. The body may also get less oxygen, so it has less energy. Anemia can be treated by taking iron supplements or through a blood transfusion.

If you are not sure why your child is having a blood test, ask the clinic nurse. For your own peace of mind, it's good to know what is going on.

How is blood work done?

For some blood tests, only a finger prick is needed. For other tests, your child will need to have blood taken (drawn) with a needle at a blood work clinic. This will not take a long time.

A nurse or a technician who is trained to take blood (a phlebotomist) will draw your child's blood. This person will roll up your child's sleeve and tie an elastic band around the arm, above the area where the blood will be drawn. Then they will rub alcohol or antiseptic over the vein and insert the needle. Blood is drawn into special small, air-tight tubes called vials which are labelled and sent off for analysis.

The elastic is removed when enough blood is taken to let the blood flow normally. To stop the bleeding, the nurse or technician will give you a cotton swab to press on the needle site, followed by a bandage.

Will the needle hurt your child?

A local anaesthetic cream may be given to help reduce the pain involved when blood is taken. Your child may experience some minor bruising or throbbing where the needle was inserted. This will disappear in a day or two. Some children feel faint when they have blood drawn.

How can you help your child through blood work?

Getting a needle is not a fun experience. And it can be upsetting for many parents to see their children have needles. Experienced nurses can give needles almost painlessly and it does not take long at all. As a parent, you can help your child by reassuring them while they get a needle. Explain that it will not be more painful than a pinch and that it will be over quickly. Remember, though, that sometimes more than one try is needed to obtain enough blood.

Encourage your child to be strong and reinforce that, while needles may look frightening, they are not dangerous. Talking calmly to your child will help. Also, giving them a favourite toy to hold onto may make it easier. Taking deep, slow breaths, and having them look away from the needle can also help.

Last updated: December 11th 2009