Along with the liquid called plasma, your blood contains red cells, white cells, and platelets. Platelet-rich plasma (PRP) is obtained via a process called centrifugation that removes red and white blood cells from a blood sample while leaving behind a high concentration of platelets in the plasma.
Platelets are vital for clotting blood but also contain proteins called growth factors that are very important in the healing process. PRP contains as many as 10 times the normal concentration of platelets.