The mystique of the erythrocyte sedimentation rate. A reappraisal of one of the oldest laboratory tests still in use.

The ESR is a commonly performed laboratory test with intriguing antecedents extending back to the classical period of Western medicine. Although this background was appreciated by the physicians who popularized the test in the early part of this century, it has been largely forgotten. There has always been a lack of consensus about the role of the ESR as a nonspecific indicator of inflammation and tissue injury. The usefulness of the sedimentation rate has decreased as new methods of evaluating disease have been developed. It remains helpful in monitoring certain inflammatory processes, particularly rheumatoid arthritis, and it is of great value in the diagnosis of temporal arteritis and polymyalgia rheumatica. The use of the ESR as a screening test to identify patients who have significant disease is not supported by the literature. The basic factors influencing the sedimentation rate were understood by the early decades of this century and the most satisfactory method of performing the test was introduced by Westergren in 1921. The complex nature of the factors influencing test outcome have precluded development of a reference method or of an easily implemented quality control program. Current interest in the methodology of the ESR focuses on the development of automated closed systems that allow determination of the sedimentation rate in the collection tube. These methods offer advantages of speed, safety, and uniform specimen handling. Systems utilizing sedimentation columns less than 200 mm in length may be less sensitive to changes at higher ESRs than the Westergren method. Laboratories should consider using a closed or a closed and automated system as their routine method for performing the ESR.