Erythrocyte Sedimentation Rate (ESR)
Reviewed
Also called: SED rate, sedimentation rate, Westergren sedimentation rate
An erythrocyte sedimentation rate (ESR) is a blood test that can show if you have inflammation in your body.
Specimen: blood
Why this test may be ordered
- To help diagnose conditions that cause inflammation, such as arthritis, vasculitis, infections, and inflammatory bowel diseases
- To monitor an existing condition that causes inflammation
- When you have symptoms of inflammation like headaches, unexplained fever, unexplained weight loss, joint stiffness, neck or shoulder pain, loss of appetite, or anemia
Preparation and collection
You don't need any special preparations for this test. But if your provider ordered other tests on your blood sample, you may need to fast (not eat or drink) for several hours before the test.
A health care professional will take a blood sample from a vein in your arm, using a small needle. This usually takes less than five minutes.
There is very little risk to having an ESR. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.
Understanding results
Your provider will use your ESR test results, medical history, symptoms, and other test results to make a diagnosis. An ESR test alone cannot diagnose conditions that cause inflammation.
What does a high ESR mean?
High ESR (red blood cells sank faster than normal): A high ESR test result means your red blood cells sank faster than normal. This may be from a condition that causes inflammation, such as: giant cell arteritis, inflammation (swelling) of your arteries, usually in your scalp, neck, and arms; arthritis; systemic vasculitis, inflammation of your blood vessel walls, which can affect any of your organs; polymyalgia rheumatica; inflammatory bowel disease; kidney disease; infections; rheumatoid arthritis and other autoimmune diseases; heart disease; certain cancers. Limitation: If your ESR results are not normal, it doesn't always mean you have a medical condition that needs treatment. Normal ESR levels will vary, depending on your age and sex. Next step: Because an ESR can't diagnose a specific disease, your provider may order other tests at the same time.- Low ESR (red blood cells sank slower than normal): A low ESR test result means your red blood cells sank slower than normal. This may be caused by conditions such as: A blood disorder, such as: polycythemia, an increase in your red blood cells, which causes your blood to thicken; sickle cell disease (SCD); leukocytosis, a very high white blood cell count (WBC); heart failure; certain kidney and liver problems. Limitation: Also, pregnancy, your menstrual cycle, aging, obesity, drinking alcohol regularly, and exercise can affect ESR results. Next step: Your provider will use your ESR test results, medical history, symptoms, and other test results to make a diagnosis.
- An ESR test alone cannot diagnose which condition is causing inflammation.
- It is possible to have a condition that causes inflammation and still have a normal ESR result.
- Normal ESR levels vary based on age and sex.
- Factors like pregnancy, menstrual cycle, aging, obesity, regular alcohol consumption, exercise, and certain medicines or supplements can affect ESR results.
- The test does not provide a specific diagnosis; it is a nonspecific marker of inflammation.
What to do next
Because an ESR can't diagnose a specific disease, your provider may order other tests at the same time. A C-reactive protein (CRP) test is commonly done with an ESR to provide more information.
- Do I need to do anything special to prepare for an ESR test?
- What are the risks or side effects of having an ESR blood draw?
- What does it mean if my ESR result is high?
- Can my ESR be normal even if I have inflammation?
- What other tests might my provider order along with an ESR?
Evidence source
Source: U.S. National Library of Medicine (MedlinePlus). Practices and reference ranges may differ in your country.
U.S. National Library of Medicine: Erythrocyte Sedimentation Rate (ESR)