ABSTRACT
For practical purposes, therefore, this chapter will discuss only frozen red blood cells, often called “frozen b lo o d ”. The indications for cryopreservation o f red blood cells are show n in Table 39.1. B lood from a d o n o r w ith a very Rare phenotype (rare b lood group), w hen the frequency is less th a t 1:500 is an im p o rtan t indica tion . Such a b lood type is usually in sh o rt supply and dem and is variable and unpredictable. The second clinical s ituation is m ore com m on and arises w hen the donor(s) is know n to lack red cell antigens to w hich a llo im m unization is com m on. For exam ple, patients w ith sickle cell disease (C hapter 17) have a tendency to form m ultip le alloantibodies after red cell transfusions. Red cells from patients w ith sickle cell disease frequently lack com m on Rhesus antigens, designated C and E, and o ther m in o r antigens such a Kell (K), K idd (JKb), and b o th o f the two com m on antigens w ith in the Duffy system (Fy3, Fy*5). It is difficult in practice for transfusion services and often b lood centers to have this b lood available on d e m and in the liquid state. The th ird indication occasionally used for cryopreservation o f b lood is autologous b lood donation . Two different clinical situations can occur here: the autologous b lood d o n o r w ith a rare b lood group or m ultip le antibodies, w here cryopreservation m ay be appropriate . A second situation is w here surgery is unexpectedly canceled. A lthough in practice, b lood centers do n o t like to cryopreserve autologous b lood because o f cost and logistics, there m ay be exceptions; for exam ple, w hen elective surgery has to be deferred for approxim ately 3-4 weeks, o r w here two p lanned procedures separated by only a few weeks are anticipated. W ith o u t cryopreservation, the p a tien t could undergo surgery in an anem ic state w ith allogeneic transfusion possibly required. If the surgery can be deferred for a m ore extended tim e period , e.g., th ree m onths, it m ay be be tte r to discard the
Clinical Transfusion Medicine, by Joseph D. Sweeney and Yvonne Rizk. © 1999 Landes Bioscience
Table 39.1. Possible indications for cryopreservation o f red cells (frozen blood) and platelets
liquid b lood w ith o u t cryopreservation and recom m ence a p^edeposit schedule p rio r to the new in tended date o f surgery (C hapter 3). C ryopreservation o f a u tologous blood w ith the in tention for use in an emergency situation, such as traum a, is costly, inappropria te and logistically im practical. The need to transfuse b lood urgently will n o t allow the tim e consum ing task o f deglycerolization and hence, this practice should be discouraged.
