The
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. It is a common
hematology test, and is a non-specific measure of
inflammation. To perform the test, anticoagulated
blood was traditionally placed in an upright tube, known as a Westergren tube, and the rate at which the
red blood cells fall was measured and reported in mm/h.