(b) Second, the post-reaction, anticoagulated sample should be
examined for evidence of hemolysis and the direct antiglobulin test performed. If there
is no hemolysis and the direct antiglobulin test is negative, it is unlikely that a hemolytic
reaction has occurred; however, if hemolysis is noted in the post-reaction specimen or if
the direct antiglobulin test is positive (and was negative prior to transfusion), the
physician caring for the recipient should be notified immediately so that he may begin
appropriate therapy. Then the blood bank should search further for the etiology.
(c) Third, a complete evaluation should be initiated. This evaluation
should include major (and, if necessary, minor) cross-matches using both pre-reaction
and post-reaction serum samples versus RBCs from integral tubing or obtained from
inside the blood bag. The ABO (direct and reverse) and Rh type of the recipient and the
cells in the bag should also be (re)determined; the plasma in the bag should be
examined for the presence of hemolysis that may indicate improper handling of the
blood following collection or the presence of bacterial contamination. If the latter is
suspected, the unit of blood should be cultured at both 37C and at room temperature.
Remember, hemolysis may occur without serologic evidence of incompatibility.
(3) Two minor points to keep in mind regarding evaluation of a hemolytic
transfusion reaction are: (1) testing for haptoglobin and (2) follow-up serologic tests if no
RBC antibody is detectable. With visible hemolysis, the haptoglobin-binding capacity of
serum is already exceeded and the level is nil. Documenting this absence of
haptoglobin is thus rarely of value. If no antibody is detected at the time of hemolysis
because of immune destruction of RBCs, it may have all been consumed during the
reaction. Testing serum samples drawn a few days later will often reveal the amnestic
return of the antibody.
e. Reactions Caused by Bacterial Contamination.
(1) Contamination of blood or components with bacteria occurs very rarely.
Transfusion of blood with bacteria may produce a severe and life-threatening reaction,
characterized by the rapid onset of chills, high fever, vomiting, diarrhea, marked
hypotension, and often-acute renal tubular necrosis. In the past, most severe reactions
were caused by gram-negative organisms capable of proliferating at refrigerator storage
temperatures; gram-positive organisms were infrequently implicated, presumably
because of their inability to multiply at those temperatures. Open procedures for
Ieukapheresis, plateletpheresis, RBC glycerolization, and deglycerolization all have the
potential for introduction and proliferation of bacteria; components prepared by these
techniques must be used within 24 hours. Contamination of l.V. solutions or wash
solutions used with blood components should also be considered when a reaction to
bacteria is suspected.