Blood Tests for Children: What You Should Know

Blood tests for children can give us a lot of information about their health. We'll tell you everything you need to know about them.
Blood Tests for Children: What You Should Know

Last update: 12 April, 2021

Blood tests are laboratory tests. Sometimes, they’re necessary to provide pediatricians with more information about a child’s health status or to make more accurate diagnoses. In this article, we’ll tell you everything you need to know about blood tests in children.

What is a blood test?

A blood test is a laboratory test that’s performed from a sample of blood that’s drawn from the person. In these tests, the professional will measure the different substances that make up the blood. 

Normally, when a doctor requests a blood test, they don’t ask for every single substance to be measured. Laboratory tests are usually requested based on the child’s clinical and physical examination.

Analyzing the normal components of the blood will already give us a lot of information about someone’s state of health. However, professionals can perform other tests with a blood sample as well.

Blood Tests for Children: What You Should Know

What information do blood tests give us?

The most commonly measured parameters are:

  • Hemogram: they measure the cellular component of the blood. They can determine if you have anemia or other infections.
  • Coagulation: this is important before any surgery or in the case of some diseases.
  • Lipid profile: indicates the level of triglycerides and cholesterol.
  • Proteins that indicate infection or inflammation.
  • Blood glucose: important to assess the management of glucose in the blood. It could point to diabetes.
  • Professionals may look at some organ functions, such as kidney or liver.

How do they perform them?

To carry out a blood test, the professional will draw a sample of blood. The extraction process isn’t very pleasant, but it’s also not very painful. A specialist will draw blood from a vein, usually one that’s in the arm, with a small needle. They’ll use a finer needle for children than the one they use for adults. Then, they’ll draw the blood until they have the amount they need, which is dependent on the type of analysis.

Although it’s a quick process, and it only takes a few minutes to complete, there are children who are very afraid of it. This could be because of the environment of the health center or hospital, the needle, the medical staff, etc.

Therefore, it’s important that you prepare your child in advance by reassuring them and letting them know that it will be quick. In addition, you can remind them that the procedure is necessary and that the calmer they are, the less it will hurt.

Normally, the parent, or whoever is accompanying the child, will be able to stay with the child while the specialist draws their blood. Also, it may be helpful for the child to look away from the needle when they’re inserting it. Often, if the child looks at the needle, they’re increasing the chance of feeling distressed or of being dizzy and fainting.

Blood Tests for Children: What You Should Know

Read more: Prenatal Tests During the Third Trimester of Pregnancy

When are blood tests for children necessary?

There’s no scientific evidence to recommend performing blood tests for children who are healthy during their routine check-ups with the pediatrician. However, there will be many occasions when, for some specific reason, the pediatrician or specialist will want a blood test. Some of the most common situations are:

  • Familial hypercholesterolemia (genetically caused high cholesterol levels).
  • Diabetes and other metabolic diseases.
  • Chronic and hormonal diseases.
  • To control the level of some medications, such as antiepileptic medication.
  • Immunodeficiencies.
  • Children with cancer.

As for blood tests for children, you should know…

Although they’re not included in your healthy child’s routine check-ups, blood tests can often provide us with a lot of information about their health status. The specialist will be the one who decides when it’s appropriate to order a blood test and what parameters need to be looked at.


All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.