What percentage of red blood cells must be retained when preparing red blood cells leukocytes reduced?

There are a variety of blood products, pharmacologic agents, and procedures that can be utilized to treat anemia, thrombocytopenia, and bleeding disorders. Here is a brief overview of the products and services available:

Product	Description
	Packed red blood cells (PRBCs) are made from a unit of whole blood by centrifugation and removal of most of the plasma, leaving a unit with a hematocrit of about 60%. One PRBC unit will raise the hematocrit of a standard adult patient by 3% (or about 1%/mL/kg in a child - 12%/25 kg with the standard 300 mL PRBC unit). PRBCs are used to replace red cell mass when tissue oxygenation is impaired by acute or chronic anemia.
	FFP contains all factors of the soluble coagulation system, including the labile factors V and VIII. FFP is indicated when a patient has MULTIPLE factor deficiencies and is BLEEDING. Note that FFP SHOULD NEVER be used as a plasma expander.
	Cryoprecipitate (cryo) contains a concentrated subset of FFP components including fibrinogen, factor VIII coagulant, vonWillebrand factor, and factor XIII. Cryoprecipitate is used for hypofibrinogenemia, vonWillebrand disease, and in situations calling for a "fibrin glue." Cryo IS NOT just a concentrate of FFP. In fact, a unit of cryo contains only 40-50% of the coag factors found in a unit of FFP, but those factors are more concentrated in the cryo (less volume).
	A single platelet unit is derived from one whole blood unit collected. Platelets are stored at room temperature and CANNOT be frozen. They must be used in 5 days. Pooled platelets from multiple donors from whole blood collections are cheaper to produce but the exposure to the recipient increases.
	A "six pack" of platelets can be obtained by apheresis from a single donor at one time. Thus, apheresis platelets give just "one donor" exposure to the recipient, but the cost is high. The recipient's HLA type can be "matched" to a platelet donor with a similar HLA type to deal with problems of HLA alloimmunization (in patients with prior transfusions or pregnancies). The expected incremental increase in platelet count for adults is 30 - 60 K for each "six pack" of platelets
	Normal saline is used when providing vascular access and fluid volume when transfusing other products and pharmacologic agents. Normal saline is more readily accessible than albumin or FFP, it is relatively inexpensive, and it does not have the risk of viral transmission.
	Albumin is useful as a plasma expander. Albumin is not always readily accessible and it is expensive, but it does not have risk of viral transmission.
	Whole blood (WB) is preferred for resuscitation of severe traumatic hemorrhage. WB has RBCs for oxygen delivery, but also contains coagulation factors and platelets more concentrated than in separately transfused components. In emergent scenarios, group O blood ("universal donor") blood screened low titers of anti-A and -B antibodies can be selected for storage as "low titer O whole blood" (LTOWB).
	Apheresis involves removal of whole blood from either a patient undergoing treatment or a donor who is providing a blood component (typically platelets). Using an instrument designed as a centrifuge, the components of whole blood are separated. One of the separated portions is withdrawn and the remaining components are retransfused. The components which are separated off and withdrawn include: plasma (plasmapheresis), platelets (plateletpheresis), and leukocytes (leukapheresis).

There are specialized blood products for situations in which cells or substances in the unit need to be reduced or removed:

How is leukocyte reduced red blood cells prepared?

What percentage of red blood cells make up the volume of blood cells?

What is Red Cell 30 min rule?

What is the percent of red blood cells in a sample of blood?