The Erythrocyte Sedimentation Rate (ESR) is a blood test which measures the rate at which red blood cells (erythrocytes) settle at the bottom of a tube over a specific period, usually 1 hour. The ESR is affected by the presence of plasma proteins, such as fibrinogen, IgM, alpha2-macroglobulin and other acute phase proteins, which encourage erythrocyte agglomeration. It is important to note that while ESR is a useful tool, it is not specific to any particular disease. A high ESR can be seen in various conditions, and additional tests are often needed to achieve an accurate diagnosis. The ESR, therefore, forms a part of a broader spectrum of diagnostic tools which healthcare professions use to assess and monitor inflammatory and infectious disease.
Preparation of patients: There is no physical preparation for the ESR test.
Precautions: The ESR should not be used to screen healthy persons for disease.