What is a Westergren tube?

To perform An erythrocyte sedimentation rate (ESR), also called a sedimentation rate or Westergren ESR, is the rate at which red blood cells sediment in a period of one hour. anticoagulated blood is placed in an upright tube, known as a Westergren tube, and the rate at which the red blood cells fall is measured and reported in mm/h. It is a common hematology test, It is a simple glass tube with marking on the side to measure the layers formed when blood separates.