Sedimentation is a physical process using gravity to remove suspended solids from liquids.
In Clinical application, the Sedimentation technology is used for Red Blood Cell analysis. The Erythrocytes Sedimentation Rate (ESR) is the rate at which red blood cells sediment or falls in a period of one hour (reported in mm). It is a common hematology test and is a non specific measure of inflammation.
To perform this test, anticoagulant blood was usually placed in an upright tube, knwn as the Westergrn tube.
With the progress of automation, ESR tests have been automatically performed.
The ESR is increased in inflammation, pregnancy, anemia, autoimmune disorders (such as rheumatoid arthritis and lupus), infections, some kidney diseases and some cancers (such as lymphoma and multiple myeloma). The ESR is decreased in polycythemia, hyperviscosity, sickle cell anemia, leukemia, low plasma protein (due to liver or kidney disease) and congestive heart failure.