ESR stands for erythrocyte sedimentation rate. It is commonly called a "sed rate."
It is a test that indirectly measures the level of certain proteins in the blood. This measurement correlates with the amount of inflammation in the body.
A blood sample is needed. Most of the time, blood is
located on the inside of the elbow or the back of the hand. The blood sample is sent to a lab.
The test measures how fast red blood cells (called erythrocytes) fall to the bottom of a tall, thin tube.
There are no special steps needed to prepare for this test.
You may feel slight pain or a sting when the needle is inserted. You may also feel some throbbing at the site after the blood is drawn.
Reasons why a "sed rate" may be done include:
Unexplained fevers
Certain types of joint pain or arthritis
Muscle symptoms
Headache
Other vague symptoms that cannot be explained
This test may also be used to monitor whether an illness is responding to treatment.
It is not used to diagnose a specific disorder.
However, the test is useful for detecting and monitoring:
Certain forms of arthritis
Inflammatory diseases
For adults (Westergren method):
Men under 50 years old: less than 15 mm/hr
Men over 50 years old: less than 20 mm/hr
Women under 50 years old: less than 20 mm/hr
Women over 50 years old: less than 30 mm/hr
For children (Westergren method):
Newborn: 0 to 2 mm/hr
Newborn to puberty: 3 to 13 mm/hr
Note: mm/hr = millimeters per hour
Normal value ranges may vary slightly among different labs. Talk to your health care provider about the meaning of your specific test results.
Erythrocyte sedimentation rate; Sed rate; Sedimentation rate
Deane KD, Pisetsky DS. Laboratory testing in the rheumatic diseases. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 237.
Vajpayee N, Graham SS, Bem S. Basic examination of blood and bone marrow. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 31.
Updated by: Frank D. Brodkey, MD, FCCM, Associate Professor, Section of Pulmonary and Critical Care Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.