This International Standard specifies requirements for single-use and re-usable glass and plastics tubes for measuring the erythrocyte sedimentation rate (ESR) by the Westergren method, and for a support to hold tubes during the performance of the test. These so-called “Westergren tubes” are also sometimes designated as “Westergren pipettes”. A procedure for measuring the erythrocyte sedimentation rate by the Westergren method is given in informative Annex D. This International Standard does not apply to single-use containers for human venous blood specimen collection and their accessories for which other standards apply. It also does not apply for devices where the Westergren method has been used as basis to develop other, similar methods or equipment for the erythrocyte sedimentation rate determination.