These tubes are specically designed to be used for 1mL blood samples which will be assayed both for 8-isoprostanes and prostaglandins. See benefits of tubes D31007 and D31008.|The tubes are graduated, with a silicone washer sealed and external threads. They can be stored at temperatures as low as -80 degrees. Thus, BHT Indomethacin sampling tubes may be useful for any lipid peroxidation and COX metabolites studies.