Method and apparatus for determining the erythrocyte sedimentation rate

摘要

In an improved method for measuring the erythrocyte sedimentation rate (ESR) a pre-evacuated test tube (T) is used to collect a blood specimen. The tube (T) is made of a material such as glass or plastics and contains an anticoagulant/mixing agent. For testing, the tube (T) is put into a rack (1) and loaded into an instrument which mixes the specimen briefly. An optical sensor (3) is used to record the location of the blood/air meniscus at initial time. At subsequent time intervals thereafter for periods up to 20 minutes or less, the optical sensor (3) identifies and measures the location of the cell/plasma interface (I) within an observation window constituting a minor portion of the overall length of the tube (T). The measured value is then converted by an algorithm (10, 11) to the value which would be obtained using the classical Westergren method.