These ESR tubes are manufactured by Chargen Life Sciences. The 1.8 ml ESR vacuum tubes are used for collecting blood and for anticoagulation for sedimentation rate test. These 1.8 ml ESR tubes contain a 3.8% buffered trisodium citrate solution with the mixing ratio of 1:4 citrate to blood. ESR measurement is done as per the Westergren method. SR stands for Erythrocyte Sedimentation Rate. An ESR test measures the rate at which the RBCs or the red blood cells undergo sedimentation i.e. how quickly they settle down at the bottle of the tube. ESR is said to be higher when the rate of RBC sedimentation is high. This can happen in case of an infection or inflammation.

Sodium citrate is used as anticoagulant which means that it prevents blood from clotting. Sodium citrate acts as an effective anticoagulant because of its mild calcium-chelating properties. Adding sodium citrate to blood prevents it from clotting. Sodium citrate is the preferred anticoagulant because factor V is relatively stable in citrated blood. All kinds of blood cell properties are analysed using these tubes like, blood cell morphology,blood cell count,hematocrit test,hemoglobin, and sickling test among others.

The tubes are 13 x 75 mm in dimensions and are made of high quality PET material. They have a black cap, are disposable and sterile and have a shelf life of 18 months.