The sed rate (erythrocyte sedimentation rate or ESR) test is a type of blood test. It helps healthcare providers check for inflammation inside your body. They might use it to help diagnose a condition or infection, or to monitor you for changes after starting a new treatment.
Erythrocytes are red blood cells. The sedimentation rate is the time it takes for your red blood cells to settle at the bottom of a test tube. An erythrocyte sedimentation rate (ESR) is a blood test that can show if you have inflammation in your body.
An erythrocyte sedimentation rate (ESR) test, also called a sedimentation rate test or sed rate test, measures how quickly red blood cells sink to the bottom of a test tube.