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What Is a Blood Test?

By taking and testing a small sample of a person’s blood, doctors can check for many kinds of diseases and conditions. Blood tests help doctors check how the body’s organs are working and see if medical treatments are helpful.

To help your child get ready for a blood test, find out if they need to fast (not eat or drink) or should stop taking medicines before the test. Explain what to expect during the test. If your child is anxious about it, work together on ways to stay calm.

What Is a Blood Culture?

A blood culture is a test that looks for germs (such as bacteria or fungi) in the blood. If germs are found, the test also can help doctors know which medicines will work best to treat the infection.

Why Are Blood Cultures Done?

Doctors may order a blood culture if a child has signs of an infection that could be caused by bacteria or fungi. It also might be done if a child has an infection in one part of the body that may have spread into the blood.

What if I Have Questions?

If you have questions about the blood culture or what the test results mean, talk to your doctor.

Medically reviewed by: Larissa Hirsch, MD
Date reviewed: March 2023