What Is ESR (Erythrocyte Sedimentation Rate) & Why Is It Used?

How Does an ESR Test Work?

Erythrocytes are red blood cells. An ESR test checks how quickly these red blood cells sink to the bottom of the test tube. 

Normally, red blood cells sink slowly. However, if you have inflammation, your red blood cells will get stuck together in clumps, causing them to sink faster. The speed at which the red blood cells sink to the bottom will indicate the level of inflammation you have. A faster ESR rate would mean higher levels of inflammation. 

What Diseases Can an ESR Test Help Diagnose?

As discussed, an ESR rate helps determine the level of inflammation in the body. Therefore, it can help your doctor diagnose the presence of conditions that cause inflammation, like:

• temporal arteritis
• autoimmune diseases
• cancers, and
• infections

Your doctor may also prescribe this test while evaluating unexplained fever, some type of arthritis or connective tissue problems like polymyalgia rheumatica. 

An ESR test can also help monitor certain autoimmune inflammatory conditions like rheumatoid arthritis and systemic lupus erythematosus (SLE).

When do Doctors Recommend an ESR test?

Your doctor may recommend an ESR test if you have the following symptoms:

• Headaches
• Unexplained fever
• Abnormal weight loss
• Stiffness in joints
• Pain in the neck or shoulder
• Loss of appetite
• Anaemia
• Digestive problems like diarrhoea

What Happens During an ESR Test?

It's a simple blood test in which a healthcare professional will take a sample from a vein in your arm using a small needle. The blood sample will be collected in a test tube or vial which will then be sent to the lab for testing. The entire process takes less than 5 minutes.

Do I Need To Prepare in Advance for an ESR Test?

This test does not require any special preparation. However, you must inform your doctor of all the medications that you are taking. They may ask you to temporarily stop certain medications before the test. 

Are There Any Risks and Complications Involved in the Test?

Usually, there is no risk involved in an ESR test. However, you may experience slight pain or bruises at the spot where the needle was inserted.

What Are the Normal ESR Test Results?

ESR test results are measured in the form of millimetres per hour (mm/hr). The normal ESR level for men is 0 to 22 mm/hr and for women is 0 to 29 mm/hr. A higher value can indicate the presence of inflammation in the body.

An ESR test result higher than 100 mm/hr may indicate a more serious health condition like cancer, diabetes or cardiovascular disease.

What Does an Abnormal ESR Test Result Mean?

As discussed earlier, an ESR test does not diagnose any specific disease. It only helps identify potential inflammation in the body and indicates your doctor to look further into it.

A high ESR request result can be indicative of inflammatory conditions like arteritis, arthritis, systemic vasculitis, polymyalgia rheumatica, inflammatory bowel disease, kidney disease, infection, rheumatoid arthritis, heart diseases, certain cancers, etc.

A low ESR test result, on the contrary, may be caused by heart failure, certain kidney and liver problems and blood disorders like polycythemia, sickle cell disease (SCD) and leukocytosis. 

However, you must note that an abnormal ESR test result does not necessarily always indicate a medical condition. Many factors affect ESR, like older age, pregnancy, menstruation and certain medications. Therefore, you must not worry if your ESR test results are abnormal. Instead, work with your doctor to find the root cause behind these results.

In addition, it is also possible to have an inflammatory condition and still receive a normal ESR test result. Therefore, doctors usually prescribe a C-reactive protein (CRP) test to obtain more information.

On a Final Note

An ESR test can help diagnose the level of inflammation in the body and indicate the presence of inflammatory conditions like rheumatoid arthritis, inflammatory bowel disease, certain cancers and infections. It is an easy blood test that does not require any preparation or include any risk.

References

• https://medlineplus.gov/lab-tests/erythrocyte-sedimentation-rate-esr/
• https://www.mayoclinic.org/tests-procedures/sed-rate/about/pac-20384797
• https://www.healthline.com/health/esr
• https://www.mountsinai.org/health-library/tests/esr
• https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=167&contentid=erythrocyte_sedimentation_rate