Erythrocyte Sedimentation Rate Test (ESR) – Why am I having this test?
Erythrocyte sedimentation rate test is used to help find illnesses related to:
- Sudden (acute) or long-term (chronic) infections.
- Inflammation.
- The body’s disease-fighting system attacking healthy cells (autoimmune diseases).
- Cancer.
- Tissue death.
If you have symptoms that may be related to any of these illnesses, your health care provider may do an ESR test before doing more specific tests. If you have an inflammatory immune disease, such as rheumatoid arthritis, you may have this test to help monitor your therapy.
What is being tested?
This test measures how long it takes for your red blood cells (erythrocytes) to settle in a solution over a certain amount of time (sedimentation rate). When you have an infection or inflammation, your red blood cells clump together and settle faster. The sedimentation rate provides information about how much inflammation is present in the body.
What kind of sample is taken?
A blood sample is required for this test. It is usually collected by inserting a needle into a blood vessel.
How do I prepare for this test?
Follow any instructions from your health care provider about changing or stopping your regular medicines.
Tell a health care provider about:
- Any allergies you have.
- All medicines you are taking, including vitamins, herbs, eye drops, creams, and over-the-counter medicines.
- Any blood disorders you have.
- Any surgeries you have had.
- Any medical conditions you have, such as thyroid or kidney disease.
- Whether you are pregnant or may be pregnant.
How are the results reported?
Your results will be reported as a value that measures sedimentation rate in millimeters per hour (mm/hr). Your health care provider will compare your results to normal ranges that were established after testing a large group of people (reference values). Reference values may vary among labs and hospitals. For this test, common reference values, which vary by age and gender, are:
- Newborn: 0–2 mm/hr.
- Child, up to puberty: 0–10 mm/hr.
- Female:
- Under 50 years: 0–20 mm/hr.
- 50–85 years: 0–30 mm/hr.
- Over 85 years: 0–42 mm/hr.
- Male:
- Under 50 years: 0–15 mm/hr.
- 50–85 years: 0–20 mm/hr.
- Over 85 years: 0–30 mm/hr.
Certain conditions or medicines may cause ESR levels to be falsely lower or higher, such as:
- Pregnancy.
- Obesity.
- Steroids, birth control pills, and blood thinners.
- Thyroid or kidney disease.
What do the results mean?
Results that are within reference values are considered normal, meaning that the level of inflammation in your body is healthy. High ESR levels mean that there is inflammation in your body. You will have more tests to help make a diagnosis. Inflammation may result from many different conditions or injuries.
Talk with your health care provider about what your results mean.
Questions to ask your health care provider
Ask your health care provider, or the department that is doing the test:
- When will my results be ready?
- How will I get my results?
- What are my treatment options?
- What other tests do I need?
- What are my next steps?
Summary
- The erythrocyte sedimentation rate (ESR) test is used to help find illnesses associated with sudden (acute) or long-term (chronic) infections, inflammation, autoimmune diseases, cancer, or tissue death.
- If you have symptoms that may be related to any of these illnesses, your health care provider may do an ESR test before doing more specific tests. If you have an inflammatory immune disease, such as rheumatoid arthritis, you may have this test to help monitor your therapy.
- This test measures how long it takes for your red blood cells (erythrocytes) to settle in a solution over a certain amount of time (sedimentation rate). This provides information about how much inflammation is present in the body.
