A recent National Heart, Lung, and Blood Institute expert panel concluded that despite
significant reduction in the risk of transfusion transmitted viruses, the transfusion of
autologous blood remains safer than that of allogeneic blood and is appropriate for
properly selected patients. Exclusive or supplemental use of autologous blood can prevent
adverse effects of transfusion, including bloodborne viral transmission, immunologic
transfusion reactions, and sensitization. On the other hand, collection of autologous
blood in patients with a low probability of transfusion (hence, a high discard rate of
donated units) is the major factor reducing its cost-effectiveness.
The rationale for directed donor transfusions stems largely from the
perception among the public that blood obtained from persons they know may be safer than
that from the regular volunteer donor population. Based on prevalence studies of viral
markers, however, physicians should be aware of the lack of objective evidence to support
this belief when considering transfusion options with their patients. It should also be
recognized that directed donations are not as safe as the patients own blood and
should not be considered equivalent to autologous blood donations.
Patient Selection For Autologous Donations:
Candidates for autologous donation are patients undergoing elective
surgery that is likely to require transfusion. Examples include patients who are
undergoing total hip replacement, spine surgery with instrumentation, and individuals
undergoing coronary artery bypass surgery in whom the time required to collect autologous
units will not compromise patient safety or outcome. A useful guide for estimation of the
number of units required is the hospitals maximum surgical blood order schedule
Autologous donation can be utilized in children weighing at least 65
pounds and is generally a safe procedure, even for elderly patients. However, vasovagal
reactions, which occur in 1-4% of all blood donations, may carry the risk of greater
morbidity for some patients with unstable cardiac or cerebral vascular disease. A recently
reported survey found that 1 in 16,000 autologous donors had a reaction severe enough to
warrant hospitalization. The Institutes medical staff are available to assist with
questions regarding donor suitability and the need for special monitoring. Additional
factors which determine eligibility include the absence of infection (in order to exclude
possible bacteremia and proliferation in the stored blood component) and the presence of
adequate red cell mass (hemoglobin and hematocrit 11gm/33%).
Autologous Donation Technique: Autologous units may be stored
and used as whole blood, but are usually processed into packed red blood cells; fresh
frozen plasma may also be prepared from the latter. Liquid-stored red blood cells have a
shelf-life of 35-42 days depending upon the anticoagulant. Once a surgery date is
confirmed and the physician prescribes the amount of units needed, patients may be
scheduled at one of Central Blood Banks (CBB) 20 community donor centers throughout
the area. In general, donations begin 3-4 weeks before surgery; the individual may donate
every 3 to 7 days until the requested number of units have been drawn. The last donation
should ideally be at least one week before surgery, but no less than 72 hours prior to
surgery to allow sufficient time to regenerate the patient/donors red cell mass and
blood volume. A single unit donation a few days before surgery will not be beneficial
because minimal red blood cell regeneration will occur.
Iron therapy (e.g., FeSO4 325 mg p.o. t.i.d.) is necessary
since inadequate iron reserves is the major limitation to completing the donation
schedule. This is particularly true in female donors. Should surgery be postponed, the
hospital blood bank and CBB should be contacted so that the red cells may be frozen, if
necessary. Freezing the collected units is also an option if an insufficient number of red
cell units is collected due to hematocrit deferral (less than 33%) and the patients
physician decides to reschedule surgery. This would permit additional time to collect the
prescribed amount in order to maximize availability of autologous blood and minimize
allogeneic donor exposures.
While recombinant erythropoietin therapy has also been proposed to
maximize availability of autologous blood, it is not Food & Drug Administration (FDA)-
approved for this indication. However, this strategy might permit the patient who is
already anemic to build up sufficient red blood cell mass in order to allow self-donation.
Directed Donation Procedure:
Since there is no established medical advantage in using directed donors, the same
rigorous screening criteria used to safeguard both the health of the donor and the
transfusion recipient are followed as for regular volunteer blood donors. Directed
donation requests require advanced planning to allow time for scheduling of donors, blood
collection, processing (including testing), and shipping, as well as cross-matching at the
hospital. CBBs Special Donations Department generally requests that extra donors be
recruited in order to insure that a sufficient number of compatible units are available.
It is recommended that females of child-bearing age not receive directed donations from
husbands/or sexual partners because of the risk of sensitization to minor blood group
antigens, which may cause hemolytic disease of the newborn.
Directed donations between blood relatives are gamma-irradiated using 2500 cGy in order to
prevent transfusion-induced graft-vs-host disease. Since directed donors must meet all
regular blood donor criteria, unused units may be "crossed-over" for general use
unless notified otherwise by the patients physician.
Unused autologous blood is stored for the patients peri-operative
needs until the unit outdates or until the patient is discharged (according to specific
hospital policy); it is then discarded. All CBB autologous units are labeled "For
Autologous Use Only", because many of these units do not meet the stricter standards
established for allogeneic blood. In accordance with FDA requirements, CBB performs all
regular donor testing on autologous donations. Because of the potential biohazard, units
reactive for anti-HIV 1/2, and Hepatitis B surface antigen are discarded. In instances
where markers other than these (anti-HCV, HBcAb etc.) are reactive, the patients
physician is notified and determines whether to continue the donation schedule and the
appropriateness for transfusion.
Hospital policies differ regarding comparative indications for
transfusion of autologous or allogeneic blood. Since precise indications for a blood
transfusion are often difficult to define, the lower risk for autologous blood supports a
more liberal transfusion threshold. On the other hand, because some risk of unrecognized
bacterial contamination remains, the transfusion of autologous red blood cells to the
mildly anemic or non-anemic patient who would derive no benefit is inappropriate.
Contact CBBs Donor Resources Office (412 209-7063) or Dr. Joseph E. Kiss (412 209-7326) for further information
on these important community programs.
Copies of the Transfusion Medicine Update can be obtained by contacting
Deborah Small at (412)