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Blood Test: Erythrocyte Sedimentation Rate (ESR)

Reviewed by: Larissa Hirsch, MD
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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 an ESR Test?

An ESR test measures how quickly red blood cells settle to the bottle of a test tube. Inflammation or infection can lead to extra proteins in the blood, which can make the red blood cells settle faster. When this happens, the ESR is higher.

Why Are ESR Tests Done?

Doctors may order an ESR test if a child has signs of inflammation or infection. They use ESR tests to follow conditions such as inflammatory bowel disease (IBD), arthritis, and lupus. ESR tests also can help doctors see how well treatment for inflammation or infection is working.

What if I Have Questions?

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

Reviewed by: Larissa Hirsch, MD
Date reviewed: September 2021