The<unk>  <unk>  or<unk>  is the<unk>  at which red blood cells in anticoagulated whole blood descend in a standardized tube over 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 is traditionally placed in an upright tube, known as a Westergren tube, and the distance which the red blood cells fall is measured and reported in mm at the end of one hour. Since the introduction of automated analyzers into the clinical laboratory, the<unk>  test has been automatically performed. The<unk>  is governed by the balance between pro-sedimentation factors, mainly fibrinogen, and those factors resisting<unk> , namely the negative charge of the<unk> s (zeta potential). When an inflammatory process is present, the high proportion of fibrinogen in the blood causes red blood cells to stick to each other. The red cells form stacks called rouleaux which settle faster, due to their increased density. Rouleaux formation can also occur in association with some lymphoproliferative disorders in which one or more paraproteins are secreted in high amounts. While abnormal in humans, rouleaux formation can be a normal physiological finding in horses, cats, and pigs. The<unk>  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<unk>  is decreased in polycythemia, hyperviscosity, sickle cell anemia, leukemia, chronic fatigue syndrome, low plasma protein (due to liver or kidney disease) and congestive heart failure. Although increases in immunoglobulins usually increase the<unk> , very high levels can reduce it again due to hyperviscosity of the plasma. This is especially likely with IgM-class paraproteins, and to a lesser extent, IgA-class. The basal<unk>  is slightly higher in females.
Erythrocyte sedimentation rate
Intraocular pressure
Rheumatoid factor
Carotid ultrasonography
Retinal vessel analysis
Pyelogram
Coagulation activation marker
Acute-phase protein