Two tubes, a 10 mL red top and a 7 mL lavender top, are packaged together in a sterile peel-apart pouch. This special formulation is extremely strong, dimensionally stable, and resistant to chemicals and breakage. As such, they should be drawn after tubes for coagulation studies. SST refers to serum separator tube. PST refers to plasma separator tube.
Initial activation occurs when blood enters the tube and contacts the particles on the tube wall.
To continue the activation process, it is necessary to thoroughly mix the blood and particles by inverting the tube five times. The gel forms a physical barrier between serum or plasma and blood cells during centrifugation. This provides a thick barrier that remains intact during transportation, thereby maintaining the quality of the sample for the lab analysis. It is intended for use primarily when specimens are collected and centrifuged in physician laboratories or other remote collection stations, and then transported back to the laboratory for analysis. The coating process creates a film on the tube surface that appears white and slightly cloudy.