What is the Erythrocyte Sedimentation Rate?

Erythrocyte sedimentation rate is a diagnostic tool to determine the presence of inflammation in the body. An elevated rate result does not generally point to any specific disease, only to the fact that an inflammatory process is going on inside the body. An inflammatory process is the body's natural response to injury and infection. The signs of inflammations include redness, pain, and swelling at the affected area.

The test is usually done with no special preparations. Technicians extract blood a patient's vein and process the blood in the laboratory to get the erythrocyte sedimentation rate. Due to external factors, normal values for erythrocyte sedimentation rate differ among children and adults, as well as between men and women. Women have higher ESR levels in the blood than men. Children, because of their weight, have lower ESR levels in the blood.

Normal values for men 50 years old and younger is 15 millimeters per hour or less. For men older 50, it is 20 millimeters per hour or less. In women 50 years old and younger, the normal value is 20 millimeters per hour, and for those older than 50, it is 30 millimeters per hour or less. Children's normal value is between 3 to 13 millimeters per hour.

An elevated sedimentation rate is often seen in patients with diseases such as rheumatoid arthritis and anemia, among many other inflammatory conditions. Rheumatoid arthritis is a condition involving several joints in the body, while anemia is the decrease of red blood cells in the circulation. Pregnancy may also elevate the erythrocyte sedimentation rate. A very high rate is often seen in polymyalgia rheumatica. Polymyalgia rheumatica is manifested by stiffness and pain in the shoulders or hips, and usually affects individuals older than 50.

A low erythrocyte sedimentation rate is frequently seen in conditions such as polycythemia, congestive heart failure, and sickle cell anemia. Polycythemia is a disorder where there is increased production of red blood cells in bone marrow. Congestive heart failure occurs when the heart is not capable of pumping blood to the rest of the body. Sickle cell anemia, on the other hand, is a hereditary disease characterized by the presence of abnormal sickle-shaped red blood cells.

Drugs can also affect the results of the test. Vitamin A and oral contraceptives can cause increase in value. A decrease in value is sometimes seen in patients who take cortisone or aspirin. The erythrocyte sedimentation rate is also a test used to monitor the response of certain diseases to medications given. A decreasing result after therapy is usually a sign of good response to treatment.