PF24
Encyclopedia
Plasma Frozen Within 24 Hours After Phlebotomy, commonly called FP24, PF-24, or similar names is a frozen human blood plasma
product used in transfusion medicine
. It differs from fresh-frozen plasma
(FFP) in that it is frozen within 24 hours of blood collection, whereas FFP is frozen within 8 hours. The term "FFP" is sometimes used to refer to any frozen blood plasma product intended for transfusion.
PF24 is stored, thawed, and infused with the same procedures used for FFP. Although it is technically a different product, most healthcare providers continue to refer to FFP when the actual component is PF24. It is likely that many physicians do not realize that the component used is PF24 rather than FFP.
, or TRALI. The proposed mechanism of TRALI involves antibodies from donor blood components (predominantly plasma) that are directed against human leukocyte antigen
s (HLA). These antibodies are most numerous in women who have been pregnant more than once. Thus, removing these women from the donor pool for frozen plasma was proposed as a solution to the TRALI problem (the women’s plasma could still be used for production of other components, including cryoprecipitate). However, removing roughly half of the donor pool was not a viable alternative, given the increasing need for plasma transfusion.
This approach was pioneered in the United Kingdom beginning in 2004 and in the United States beginning in 2007.
The use of PF24 has been accompanied by a decrease in the incidence of TRALI—a roughly 50% reduction in reported cases.
This does not address the question of risk from plasma in other components, particularly apheresis platelets. Removing multiparous women from this limited donor pool would likely cause too great a shortage of platelets, resulting in more deaths (due to hemorrhage) than are seen due to TRALI after platelet infusion. In addition, long-term studies on the effectiveness of PF24 in massive transfusion have not been conducted.
Blood plasma
Blood plasma is the straw-colored liquid component of blood in which the blood cells in whole blood are normally suspended. It makes up about 55% of the total blood volume. It is the intravascular fluid part of extracellular fluid...
product used in transfusion medicine
Transfusion medicine
Transfusion medicine is the branch of medicine that is concerned with the transfusion of blood and blood components. The blood bank is the section of the clinical laboratory where medical technologists process and distribute blood products under the supervision of a medical director, often...
. It differs from fresh-frozen plasma
Fresh frozen plasma
The term fresh frozen plasma refers to the liquid portion of human blood that has been frozen and preserved after a blood donation and will be used for blood transfusion...
(FFP) in that it is frozen within 24 hours of blood collection, whereas FFP is frozen within 8 hours. The term "FFP" is sometimes used to refer to any frozen blood plasma product intended for transfusion.
PF24 is stored, thawed, and infused with the same procedures used for FFP. Although it is technically a different product, most healthcare providers continue to refer to FFP when the actual component is PF24. It is likely that many physicians do not realize that the component used is PF24 rather than FFP.
History
The production of PF24 was begun in response to an increase in reported cases of transfusion-related acute lung injuryTransfusion related acute lung injury
In medicine, transfusion related acute lung injury is a serious blood transfusion complication characterized by the acute onset of non-cardiogenic pulmonary edema following transfusion of blood products....
, or TRALI. The proposed mechanism of TRALI involves antibodies from donor blood components (predominantly plasma) that are directed against human leukocyte antigen
Human leukocyte antigen
The human leukocyte antigen system is the name of the major histocompatibility complex in humans. The super locus contains a large number of genes related to immune system function in humans. This group of genes resides on chromosome 6, and encodes cell-surface antigen-presenting proteins and...
s (HLA). These antibodies are most numerous in women who have been pregnant more than once. Thus, removing these women from the donor pool for frozen plasma was proposed as a solution to the TRALI problem (the women’s plasma could still be used for production of other components, including cryoprecipitate). However, removing roughly half of the donor pool was not a viable alternative, given the increasing need for plasma transfusion.
This approach was pioneered in the United Kingdom beginning in 2004 and in the United States beginning in 2007.
The use of PF24 has been accompanied by a decrease in the incidence of TRALI—a roughly 50% reduction in reported cases.
This does not address the question of risk from plasma in other components, particularly apheresis platelets. Removing multiparous women from this limited donor pool would likely cause too great a shortage of platelets, resulting in more deaths (due to hemorrhage) than are seen due to TRALI after platelet infusion. In addition, long-term studies on the effectiveness of PF24 in massive transfusion have not been conducted.