Medically reviewed by David Ozeri, MD The erythrocyte sedimentation rate (ESR) blood test measures how quickly erythrocytes, a type of red blood cell, settle at the bottom of a test tube. It is also ...

The erythrocyte sedimentation rate test observes how quickly red blood cells fall to the bottom of a test tube. During normal circumstances, these cells descend slowly through the plasma.

Medically reviewed by Stuart Hershman, MD Blood tests are generally not used to diagnose the cause of back pain, but they are ...