Red stoppered tubes are used to accumulate whole blood that begins to clot so serum can be drawn off the centrifugation. Serum is a clear or amber colored liquid that can be drawn off with a pipette, which is need to carry out a testing in the case of a blood chemistry. The red stoppered tube contains a no anticoagulant or a clot activator. When the stoppered red tubes are plastic they should be inverted at least 5 times. Red/ gray stoppered tubes also contains a clot activator. A the bottom of this tube it contains a serum gel separator that liquefies and moves to the middle of the tube to separator the red blood cell form the serum. The red/gray stopper tube is also use for chemistry and should be inverted five times.
