How Does a Centrifuge Separate Blood Products?

Centrifuges separate blood products by generating forces that cause the denser elements to move to the bottom of the test tube and the less dense ones to move to the top. Because red blood cells are heavy, it is easy to separate them from other components. However, there are techniques lab workers can use to make the process smoother.

Most biology laboratories feature centrifuges that operate using a fixed angle or horizontal rotor. This makes the materials hit the side of the tube, before moving into their respective positions. In a laboratory environment, the lab technician places the blood into a test tube, which then goes into the centrifuge at a rate of around 600 g.

Although 600 g is a low centrifugation speed, the hemoglobin component of red blood cells makes them move to the bottom within 10 minutes. After centrifuging blood, lab technicians should use it immediately, or they should place it on ice to prevent the products mixing together. In addition, it is important to avoid warming the products using hands, which means handling them gently is essential. When putting blood through multiple centrifugation steps, it is necessary to place a mark on the tube to indicate where blood and plasma begins, for the sake of accuracy at the end of the test.