Sed rate (erythrocyte sedimentation rate, also known as ESR) is a simple blood test that helps detect inflammation in the body. The test measures the rate of fall (sedimentation) of red blood cells (erythrocytes) in a sample of blood. 

This CBC ESR is a type of blood test that measures how quickly erythrocytes (Red Blood Cells-RBC) settle at the bottom of a test tube that contains a blood sample. Normally, red blood cells settle relatively slowly. A faster than normal rate may indicate inflammation in the body.