Erythrocyte Sedimentation Rate
Does this test have other names?
ESR, sed rate
What is this test?
Erythrocyte sedimentation rate (ESR) is a blood test. It measures how quickly erythrocytes,
or red blood cells, separate from a blood sample that has been treated so the blood
will not clot. During this test, a small amount of your blood will be put in an upright
tube. A lab specialist will measure the rate that your red blood cells settle toward
the bottom of the tube after 1 hour.
If you have a condition that causes inflammation or cell damage, your red blood cells
tend to clump together. This makes them heavier, so they settle faster. The faster
your red blood cells settle and fall, the higher your ESR. A high ESR tells your healthcare
provider that you may have an active disease process in your body.
Why do I need this test?
You may need this blood test if you have symptoms of one of the diseases that may
cause ESR to go up.
You may also need this test if you have already been diagnosed with a disease that
causes a high ESR. The test can allow your healthcare provider to see how well you
are responding to treatment.
The ESR blood test is most useful for diagnosing or monitoring diseases that cause
pain and swelling from inflammation. Other symptoms may include fever and weight loss.
These diseases include:
ESR is not used as a screening test in people who do not have symptoms or to diagnose
disease because many conditions can cause it to increase. It might also go up in many
normal cases. ESR doesn't tell your healthcare provider whether you have a specific
disease. It only suggests that you may have an active disease process in your body.
What other tests might I have along with this test?
You may have other tests if your healthcare provider is doing this test to diagnose
Your provider may do an ESR alone if he or she is monitoring a disease you already
Because ESR tells your provider only what is happening right now, you may need to
have the test repeated over time.
What do my test results mean?
A result for a lab test may be affected by many things, including the method the laboratory
uses to do the test. If your test results are different from the normal value, you
may not have a problem. To learn what the results mean for you, talk with your healthcare
ESR is measured in millimeters per hour (mm/h). The normal values are:
0 to 10 mm/h in children
0 to 15 mm/h in men younger than 50
0 to 20 mm/h in men older than 50
0 to 20 mm/h in women younger than 50
0 to 30 mm/h in women older than 50
ESR above 100 mm/h is most likely caused by an active disease. For instance, you may
How is this test done?
The test requires a blood sample, which is drawn through a needle from a vein in your
Does this test pose any risks?
Taking a blood sample with a needle carries risks that include bleeding, infection,
bruising, or feeling dizzy. When the needle pricks your arm, you may feel a slight
stinging sensation or pain. Afterward, the site may be slightly sore.
What might affect my test results?
Many things that are not active diseases can increase your ESR. These include:
How do I get ready for this test?
You don't need to prepare for this test. Be sure your healthcare provider knows about
all medicines, herbs, vitamins, and supplements you are taking. This includes medicines
that don't need a prescription and any illicit drugs you may use. Tell your provider
if you ate a fatty meal recently, if you are having your period, or if you may be