Coagulation and CTAD tubes are used for examination of coagulation parameters. Coagulation tubes contain a buffered sodium citrate solution, available with a citrate concentration of 0.109 mol/l (3.2%). The mixing ratio is: 1 part citrate solution to 9 parts blood. In addition to buffered sodium citrate, CTAD tubes contain theophylline, adenosine and dipyridamol.
A polypropylene tube is put in a PET-tube. Polypropylene is chemically inert and has aPTT and PTT values that are preciser than with glass tubes (almost no impact of trombocytes).
All tubes have a paper label.