The ESR is an easy, inexpensive, non-specific test that has been used for many years to help diagnose conditions associated with acute and chronic (that is, short or long duration) inflammation, including infections, cancers, and autoimmune diseases. ESR is said to be non-specific because increases do not tell the doctor exactly where the inflammation is in your body or what is causing it, and also because it can be affected by other conditions besides inflammation. For this reason, an ESR is typically used in conjunction with other tests.
The ESR is helpful in diagnosing two specific inflammatory diseases, temporal arteritis and polymyalgia rheumatica. A high ESR is one of the main test results used to confirm the diagnosis. It is also used to monitor disease activity and response to therapy in both of these diseases.
An important use of the ESR blood test is to monitor the activity of the underlying condition causing the inflammation and the subsequent response to treatment.
A doctor usually requests an ESR test (along with others) to evaluate a patient who has symptoms that suggest polymyalgia rheumatica or temporal arteritis, such as headaches, neck or shoulder pain, pelvic pain, anaemia, unexplained weight loss, and joint stiffness. There are many other conditions that can result in a temporary or sustained elevation in the ESR and some that will cause a decrease.
Since the ESR is a non-specific marker of inflammation and is affected by other factors, the results must be used along with the doctor’s other clinical findings, the patient’s health history, and results from other appropriate laboratory tests. If the ESR and clinical findings match, the doctor may be able to confirm or rule out a suspected diagnosis. A single elevated ESR, without any symptoms of a specific disease, will usually not give the doctor enough information to make a medical decision.
Before doing an extensive investigation looking for disease, a doctor may want to repeat the ESR test after a period of several weeks or months. If a doctor already knows the patient has a disease like temporal arteritis (where changes in the ESR mirror those in the disease process), they may use the ESR at regular intervals to assist in monitoring the course of the disease. In the case of Hodgkin’s disease, for example, a sustained elevation in ESR may be a predictor of an early relapse following chemotherapy.
A rising ESR can mean an increase in inflammation or a poor response to a therapy; a decreasing ESR can mean a good response.
A common cause of high ESR is anaemia, especially if it is associated with changes in the shape of the red cells; however, some changes in red cell shape (such as sickle cells in sickle cell anaemia) lower ESR. Kidney failure will also increase ESR. People with multiple myeloma or Waldenstrom’s macroglobulinaemia (tumours that make large amounts of immunoglobulins) typically have very high ESR even if they don't have inflammation.
Although a low ESR is not usually important, it can be seen with polycythaemia (a condition where a patient makes too many red blood cells), with extreme leucocytosis (patient has too many white blood cells), and with some protein abnormalities.
The ESR and C-reactive protein (CRP) are both markers of inflammation. Generally, ESR does not change as rapidly as the concentration of CRP, either at the start of inflammation or as it goes away. CRP is not affected by as many other factors as is ESR, making it a better marker of some types of inflammation. However, because ESR is an easily performed test and CRP must be done using sophisticated laboratory equipment, many doctors still use ESR as an initial test when they think a patient has inflammation.
Females tend to have a slightly higher ESR, and menstruation and pregnancy can cause temporary elevations.
Drugs such as dextran, methyldopa (Aldomet), oral contraceptives, penicillamine procainamide, theophylline, and vitamin A can increase ESR, while aspirin, steroids, and quinine may decrease it.
This article was last reviewed on 23 April 2014. | This article was last modified on 3 June 2016.
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