The Erythrocyte Sedimentation Rate (ESR) is a traditional test used in Haematology. It is affected by the numbers of erythrocytes present in the blood, changes in plasma protein pattern, age and sex of the patient. Three phases can be distinguished in the sedimentation process: the lag phase (reflects the period in which the individual erythrocytes form rouleaux), the decantation or precipitation phase (the plasma-red cell interface falls more rapidly), and the final packing phase (the red cells aggregates pile up on the bottom of container). The ESR is dependent on the presence of agglomers, such as fibrinogen, IgM, alpha2-macroglobulin and other acute phase proteins. It is a completely non-specific test. It is a measure of the presence and severity of pathological processes. In general, the ESR is elevated in all acute, general infections, in localized, acute, inflammatory conditions, variations in the ESR depend on the nature and severity of the process. Additionally, the ESR is an important screen for occult disease. The ESR is also useful to differentiate organic disease from functional disorders, or as a guide to the progress of diseases such as rheumatic carditis, rheumatoid arthritis, and certain malignancies, including Hodgkin's disease, and is diagnostic for Temporal Arteritis.
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.
