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 . 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. Regards Dr De