Blood collection tubes are designed for drawing blood for different laboratory tests. They were firstly designed in 1947 by Joseph Kleiner. At that time they were referred to as vacutainers. However, today they are so great in number that if you’re not a professional, the choice of the right one becomes a real problem. Health care professionals are trained to differentiate the tubes by their colors, when it is needed to collect the specimen.
The majority of blood draw tubes have an additive, which prevents the blood from clotting. They also feature a clot activator that produces the serum sample, when the blood is separated by centrifugation. And an anticoagulant produces plasma sample right after the centrifugation.
Many tests require the use of plasma, some require the use of serum, the other ones – anticoagulated whole blood. They all have a vacuum that assists in the process of filling. An evacuated tube has a stopper with a septum punctured by an assembly of a needle during the collection. In most cases the stopper surrounds a plastic safety closure.