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2368 Part XIII: Transfusion Medicine Chapter 138: Blood Procurement and Red Cell Transfusion 2369

the need for allogeneic donor blood. Reactions in autologous donors leukocytes and thus can be considered leukocyte reduced. Following
are similar to allogeneic donors and are related to first-time donation, plateletpheresis, the donor’s platelet count declines by approximately 30
female gender, lower age, and lower weight. percent but returns to preplateletpheresis levels in approximately 4 days.
Autologous blood must be typed for ABO and Rh antigens. If the
unit is to be shipped to another facility for transfusion, it must be tested COLLECTION OF RED CELLS BY APHERESIS
for transmissible diseases similar to allogeneic blood. If any of the trans-
missible disease tests are positive, the unit must be labeled with a bio- Chronic shortages of group O red cells stimulated interest in the use
hazard label. of apheresis for collecting the equivalent of 2 units of red cells from
some donors, especially group O. In 2011, 1,978,000 units of red cells
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were collected by apheresis. The collection procedure is similar to
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DIRECTED DONOR BLOOD other apheresis procedures, except that red cells are retained rather than
Directed donors are friends or relatives who wish to give blood for a returned to the donor. The red cells usually have a very high hematocrit
specific patient because the patient hopes those donors will be safer (Hct) as they are removed from the instrument, but an additive solution
than the regular blood supply. However, directed donors do not have a is incorporated and the red cells can be stored for the usual 42 days. Red
lower incidence of transmissible disease markers and thus do not sup- cells obtained by apheresis have the same characteristics as those pro-
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port a realistic rationale for these donations. Because the blood becomes duced from whole blood. Because 2 U of red cells are removed, donors
part of the community’s general blood supply if it is not used for the may donate only every 4 months.
originally intended patient, directed donors must meet all the usual
FDA requirements for routine blood donation. LEUKAPHERESIS
Leukapheresis has been used to produce a granulocyte concentrate for
PATIENT-SPECIFIC DONATION transfusion therapy of infections unresponsive to antibiotics. Because
In a few situations, appropriate transfusion therapy involves collecting the efficiency of granulocyte extraction from whole blood is less than
blood from a particular donor for a particular patient. Examples are for platelets, the leukapheresis procedure involves processing 6500 to
donor-specific transfusions prior to kidney transplantation, maternal 8000 mL of donor blood for approximately 3 hours. To increase the
platelets for a fetus projected to have neonatal alloimmune thrombocy- separation of granulocytes from other blood components, hydroxyethyl
topenic purpura (NATP), or family members of a patient with a rare blood starch is added to the blood-cell–separator flow system. In addition,
type. Usually, these donors must meet all the usual FDA requirements, glucocorticoids and granulocyte colony-stimulating factor (G-CSF)
except that they may donate as often as every 3 days so long as the Hgb have been administered to granulocyte donors to increase the granulo-
remains above the normal donor minimum of 12.5 g/dL. An exception is cyte count and the granulocyte yield. 15
donation of maternal platelets for a neonate with NATP. Patient-specific
donated units must undergo all routine laboratory testing. PLASMAPHERESIS
Plasmapheresis is used to obtain plasma for manufacture of deriva-
THERAPEUTIC BLEEDING tives but not plasma for transfusion. Plasmapheresis usually can be
Blood can be collected as part of the therapy of diseases such as poly- performed in approximately 30 minutes and produces up to 750 mL
cythemia vera or primary hemochromatosis. Usually such blood is not of plasma. Because few red cells are removed, the procedure can be
used for transfusion because the donors do not meet the FDA standards repeated up to two times per week, so theoretically a donor could pro-
for donor health. As the genetic basis of hemochromatosis has become vide a large amount of plasma. Because of the nature and possible fre-
better understood, blood removed from these patients appears to be quency of plasma donation, special donor criteria apply.
safe and red cells from patients with hemochromatosis are normal dur-
ing blood bank storage, and although a blood collection program can SELECTION OF APHERESIS DONORS
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operate successfully, this has not gained general acceptance.
The selection of donors for apheresis uses the same criteria as for
COLLECTION AND PRODUCTION OF whole-blood donation with some additional donor requirements. No
BLOOD COMPONENTS BY APHERESIS more than 15 percent of the donor’s blood should be extracorporeal
during apheresis; thus, the donor’s size is considered when making
Blood components can be obtained by apheresis rather than prepared decisions about specific apheresis procedures or instruments to be used.
from whole blood. In apheresis, the donor’s anticoagulated whole blood The platelet count must be monitored for frequent donors. Because a
is passed through an instrument in which they use centrifugation to plateletpheresis concentrate would be the sole source of platelets for the
separate the blood components. Red cells, platelets, granulocytes, blood transfusion, the donor must not have taken aspirin for at least 3 days.
stem cells, mononuclear cells, and plasma can be obtained by apheresis. The amount of blood components removed from apheresis donors
must be monitored. Not more than 200 mL of red cells per 2 months or
approximately 1500 mL of plasma per week can be removed. The laboratory
PLATELETPHERESIS testing of donors and apheresis components for transmissible diseases is the
In the United States, approximately 92 percent of platelet concentrates same as for whole-blood donation. Thus, the likelihood of disease transmis-
are produced by plateletpheresis (see Table 138–1). Plateletpheresis sion from apheresis components is the same as from whole blood.
requires approximately 90 minutes, during which approximately 4000
to 5000 mL of the donor’s blood is processed through the blood cell REACTIONS IN APHERESIS DONORS
separator. The process results in a platelet concentrate with a volume of
approximately 200 mL and containing approximately 4.0 × 10 plate- Apheresis donors can experience the same kind of reactions as whole-
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lets and less than 0.5 mL red cells. Currently manufactured blood cell blood donors. In addition, apheresis donors experience a higher inci-
separators produce a platelet concentrate that contains less than 5 × 10 dence of paresthesias, probably because of the infusion of citrate (that may
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