The ESR is an easy, inexpensive, nonspecific test that has been used for many years to help diagnose conditions associated with acute and chronic inflammation, including infections, cancers, and autoimmune diseases. ESR is said to be nonspecific 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, ESR is typically used in conjunction with other tests.

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 support the diagnosis. It is also used to monitor disease activity and response to therapy in both of these diseases.

A physician usually orders 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, anemia, unexplained weight loss, and joint stiffness. There are many other conditions that can result in a temporary or sustained elevation in the ESR.

Since ESR is a nonspecific 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 physician enough information to make a medical decision.

Before doing an extensive workup 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), she may order 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.

Doctor’s do not base their decisions solely on ESR results. You can have a normal result and still have a problem.

Moderately elevated ESR occurs with inflammation, but also with anemia, infection, pregnancy, and old age.

A very high ESR usually has an obvious cause, such as a marked increase in globulins that can be due to a severe infection. The doctor will use other follow-up tests, such as cultures, depending on the patient’s symptoms. Persons with multiple myeloma or Waldenstrom’s macroglobulinemia (tumors that make large amounts of immunoglobulins) typically have very high ESRs even if they don't have inflammation. As noted before, polymyalgia rheumatica and temporal arteritis may also have very high ESRs.

A rising ESR can mean an increase in inflammation or a poor response to a therapy; a decreasing ESR can mean a good response.

Although a low ESR is not usually important, it can be seen with polycythemia, with extreme leukocytosis, and with some protein abnormalities. Some changes in red cell shape (such as sickle cells in sickle cell anemia) also lower the ESR.

ESR and C-reactive protein (CRP) are both markers of inflammation. Generally, ESR does not change as rapidly as does 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 inflammation. However, because ESR is an easily performed test, many doctors still use ESR as an initial test when they think a patient has inflammation.

If the ESR is elevated, it is typically a result of globulins or fibrinogens. Your doctor may then order a fibrinogen level (a clotting protein that is another marker of inflammation) and a serum protein electrophoresis to determine which of these (or both) is causing the elevated ESR.

Females tend to have higher ESR, and menstruation and pregnancy can cause temporary elevations.

In a pediatric setting, the ESR test is used for the diagnosis and monitoring of children with rheumatoid arthritis or Kawasaki’s Disease.

Drugs such as dextran, methyldopa (Aldomet), oral contraceptives, penicillamine procainamide, theophylline, and vitamin A can increase ESR, while aspirin, cortisone, and quinine may decrease it.