What Is It?
The Erythrocyte Sedimentation Rate (ESR) is a blood test that measures inflammation or abnormal proteins in the body. While the ESR is not an indication of any one disease, it commonly increases with any condition that causes inflammation, such as infection, arthritis, or cancer. However, up to 10% of normal, healthy people have a mildly elevated ESR and it tends to increase with age. The higher the level of ESR, the more likely the person is to have a condition known to be associated with it (see below).
Diseases Associated with Elevated ESR
Of the arthritic diseases, an elevated ESR is most closely associated with polymyalgia rheumatica (PMR) and giant cell arteritis (GCA). If disease is active, rheumatoid arthritis, systemic lupus erythematosus, vasculitic disease and almost any other inflammatory condition may be associated with an elevated ESR. Other well-established causes included subacute bacterial endocarditis (SBE), myeloma, abscess, pelvic inflammatory disease (PID), inflammatory bowel disease (IBD) and osteomyelitis. However, almost any condition that causes sudden or significant inflammation in the body can be associated with an elevated ESR.
An elevated ESR cannot establish any diagnosis by itself. Similarly, a normal ESR does not rule out an arthritic condition since many people with arthritis have a normal or only mildly elevated ESR. A normal ESR does reduce the likelihood of GCA, PMR and SBE. Thus, the ability of this test to predict presence or absence of disease is far from perfect. To rule in or rule out a condition associated with an elevated ESR, your health care provider will review your symptoms, physical examination (with special attention to the joints) and other test results.
Why Is It Ordered?
Health care providers order the ESR as a diagnostic test to help determine the cause of symptoms. For example, if you were over the age of 55 and had a new headache with shoulder and hip stiffness in the morning your symptoms and examination might suggest GCA to your doctor—checking your ESR would be appropriate. The test can also be helpful to follow the progress of disease, as a monitoring test, though the usefulness of using this test alone has not been established.
Interpreting the Result
The meaning of an elevated ESR relies on the rest of the “big picture”—if markedly elevated in the setting of symptoms and an examination suggestive of GCA or PMR, it probably indicates one of these diagnoses. On the other hand, even a moderately elevated result in someone who lacks symptoms or examination findings may have no detectable illness. In fact, the ESR may be misleading – it may suggest disease when none is present.
What Are the Next Steps?
The next step depends in large part on why the test was ordered. If normal, it may provide some measure of reassurance. If elevated, your doctors must integrate this information with your overall health, symptoms and examination results to tell whether it has any meaning. If it is only slightly elevated, there is a good chance that it is meaningless—as above, false-positive results are common, especially among older patients. It will be important over time to keep track of your symptoms over time and report any change to your doctors.
So, if you have an elevated ESR, don’t panic—keep in mind that even diseases associated with an elevated ESR cannot be diagnosed by the ESR alone. How you are feeling and what your doctors find when they examine you are much more important.
Last Updated September 2003