Plastic ESR tubes are used to determine the erythrocyte sedimentation rate. The tubes contain 3.2% sodium citrate solution as anticoagulant. VACUETTE®
ESR tubes made from PET (polyethylene terephtalate) are used for ESR determinations based on open sedimentation. The VACUETTE®
ESR tubes made from PP (polypropylene) are suitable for closed sedimentation.