Blood fractionation

The resulting components are: Serum separation tubes (SSTs) are tubes used in phlebotomy containing a silicone gel; when centrifuged the silicone gel forms a layer on top of the buffy coat, allowing the blood serum to be removed more effectively for testing and related purposes.

As an alternative to energy-consuming centrifugation, more energy-efficient technologies have been studied, such as ultrasonic fractionation.

Fractionation involves changing the conditions of the pooled plasma (e.g., the temperature or the acidity) so that proteins that are normally dissolved in the plasma fluid become insoluble, forming large clumps, called precipitate.

This procedure is carried out in a series of steps so that a single pool of plasma yields several different protein products, such as albumin and immune globulin.

[2][3] Human serum albumin prepared by this process is used in some vaccines, for treating burn victims, and other medical applications.

Blood components after centrifugation.
When blood is collected into a serum-separating tube (SST) and centrifuged, the serum becomes isolated from the red blood cells by a gel acting as a physical barrier to prevent inadvertent remixing of the components.