I. What Is Erythrocyte Sedimentation Rate (ESR) Testing?

Researchers are aware of more than 80 autoimmune disorders that can cause inflammation. Infection in any part of your body can also cause inflammatory activity.

Why should you get tested

You should get tested if you have any signs or symptoms of increased inflammation in your body, such as fever or joint pain. Testing early gives you the best chance at identifying and controlling the source of the inflammation.

Who should get tested

Anyone with signs and symptoms of inflammatory activity should have the ESR test.

When to get tested

Get tested as soon as your doctor orders the ESR test.

II. How to Prepare for Erythrocyte Sedimentation Rate (ESR) Testing

The ESR test requires no special preparation. If your doctor has ordered other blood tests, however, you may need to fast overnight or have blood drawn at a certain time of the day to get the most accurate results. For example, you may need to fast if you’re having a basic metabolic panel, which measures your electrolyte levels and checks your kidney function.

III. How an Erythrocyte Sedimentation Rate (ESR) Test Works

To have the ESR test, you’ll need to provide a blood sample, which can be done at your doctor’s office or an outpatient laboratory. Before drawing blood, a technician will tie a tourniquet around your upper arm and look for a vein to use for the blood draw. Once a suitable site has been identified, the technician will use an alcohol wipe to clean your skin, which helps prevent germs from getting into your bloodstream. When the draw site is ready, the technician will insert a needle into the vein and use a tube to collect the blood that drains out. After your blood sample arrives at the laboratory, a clinical lab professional will check to see how fast your red blood cells settle at the bottom of a tube. If your ESR is elevated, the cells will settle faster than usual.

IV. Understanding Erythrocyte Sedimentation Rate (ESR) Testing Results

Your ESR results should be ready within one to three days, depending on whether your sample was processed in-house or sent to an outside laboratory for processing. It may take your doctor another day or two to review the results and contact you to discuss them. If you have access to an online patient portal, you may be able to log in and view the results as soon as they’re ready. Even if your ESR is high, that doesn’t mean you have a medical condition that needs to be treated right away. In some cases, a woman’s ESR is elevated when she’s pregnant or menstruating. Your ESR may also be abnormal if you take aspirin, oral contraceptives, or certain supplements. If your ESR is elevated, your doctor may ask you to have other tests, such as WBC testing or a complete blood count, to determine the source of the inflammation.

V. Learn From Our Erythrocyte Sedimentation Rate (ESR) Testing Sources

To learn more about ESR testing, check out the sources used to create this guide.