Why shouldn't we determine the erythrocyte sedimentation rate?

A test that is meant to measure a given parameter is more likely to detect changes in that parameter if it is not affected by factors other than those which it is intended to quantitate. The clinical use of the laboratory test for determining the erythrocyte sedimentation rate is backed by nearly a century of experience. Although its nonspecificity is acknowledged, it has been used to quantitate the inflammatory process that underlies infectious, inflammatory, and neoplastic disorders. I believe that this venerable test is affected by too many factors in addition to that which we think we are measuring, to the point that its clinical usefulness is severely compromised.