PRP is blood plasma containing a concentration of platelets many times greater than occurs normally in blood. PRP is "autologous", meaning that it comes from the patient’s own body. This is similar to the practice of having a patient donate his/her own blood before a surgical procedure, to be used in preference to blood from the hospital blood bank should a transfusion be needed. Another example is the removal and transplantation of a patient’s own skin for a plastic surgery procedure. Because PRP is autologous, it has no potential for causing a foreign-body immunologic reaction. PRP is immunologically neutral.