A reduced erythrocyte sedimentation rate (ESR). The ESR is a test that measures the distance that erythrocytes have fallen after one hour in a vertical column of anticoagulated blood under the influence of gravity. The ESR is a nonspecific finding. A decreased ESR may be seen in polycythemia or in certain blood diseases in which red blood cells have an irregular or smaller shape that causes slower settling. [from
HPO]