Clinical and Interpretive

Erythrocyte sedimentation rate (ESR) measures the distance red blood cells fall in vitro over an hour. It is considered an indirect and nonspecific indicator of inflammation. Increased sedimentation rate occurs due to activation of fibrinogen causing erythrocytes to stick to each other. Elevated ESR occurs in physiologic conditions such as pregnancy and menstruation as well as inflammatory states. Many labs have discontinued the use of this antiquated and non-specific test.