An ESR (Erythrocyte Sedimentation Rate) test is a blood test that detects inflammation in the body. Inflammation is the immune system's reaction to infections and injury. Erythrocytes are red blood cells. For an ESR test, the patient's blood sample is collected in a thin test tube to check how fast the blood cells sink to the bottom. Healthy blood cells fall slowly, but in the case of inflammation, the blood cells stick together to form a bunch. Such a bunch drops faster as it is heavier than the single, healthy blood cells. Thus, an ESR test shows the level of inflammation in the body. Conditions like infection, unexplained fever, inflammatory bowel syndrome, and arthritis cause inflammation. An ESR test is also used to monitor the existing health conditions that could be causing inflammation. It helps diagnose the severity of inflammation and study the effects of the treatment.
Written by: Dr Vishal Wadhwa, M.D, D.N.B Microbiology, Medical Affairs