This information is useful for children and adults
Why Yale Medicine?
  • Our lab follows the highest medical safety standards and has more resources than most other centers, including a team of Blood Bank physicians on call at all times.
  • We have the most up-to-date apheresis equipment.
  • Our Yale Medicine lab often participates in clinical trials to explore new therapeutic apheresis applications.

Human blood is made up of four components: red blood cells, white blood cells, platelets, and plasma. Sometimes, to treat an illness, one of those components may need to be removed or replaced through a process called apheresis. Apheresis uses a centrifuge that separates blood into its components by density.

At Yale Medicine’s Apheresis/Transfusion Service, a team of experts works with more than 1,000 patients a year to provide safe and comfortable treatment. Yale Medicine has the most up-to-date apheresis equipment, and our site often participates in clinical trials to explore new therapeutic apheresis applications.

In traditional blood donation, a unit of whole blood is taken from a donor and sent to a laboratory, where it is separated into its four components –  red blood cells, white blood cells, platelets and plasma. The components are stored and, depending on the medical need, given to patients after surgery, an accident, illness, or following chemotherapy.

Apheresis separates the blood into these components while the donor is still connected to the separation device. A rotating centrifuge or a rotating belt separates the donor’s whole blood into its components based on density.

“Red cells are the densest, so they go to the bottom,” says Edward Snyder, MD, professor of Laboratory Medicine and director of the Apheresis/Transfusion Service at Yale Medicine. “Then next in order of density are white cells, platelets, and plasma.”

Using sterile equipment, the apheresis operator directs the needed component into a collection bag; the others return to the donor through a needle inserted into a vein in the arm. (Some patients have the blood collected and returned through a central line, a catheter inserted into a vein in the upper shoulder.)