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Transhas. Sei. Vol. 18, No. 4, pp. 585-588, 1997 © 1997 Elsevier Science Ltd. All rights reserved

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Single Donor Platelets: Can We Afford to Use Them? Can We

Afford Not to Use Them? Gary Zeger, MD*

Cleo T. Williams, MD t Ira A. Shulman, MD:~§

• One of the strategies to reduce the risk of harming a patient by transfusion therapy is to limit the overall risk of transfusion-transmitted disease. Central to this approach is minimizing the number of allogeneic blood products with which a patient is transfused. The usual dose of platelets for an adult patient is either six to 10 random donor platelets vs. one unit of platelets, pheresis (so-called single donor apher- esis platelets}. Consequently, the trans- fusion services at the University of Southern California Health Sciences Campus (USC University Hospital, the Norris Cancer Hospital, and Los Angeles County+USC Medical Center) routinely use single donor apheresis platelets (SDPs) rather than random donor platelets (RDPs} in an effort to minimize allogeneic platelet transfu- sions, and thereby reduce risk of trans- fusion-transmitted infection. Although there are other compelling medical, technical, and medical-legal reasons to use SDPs instead of RDPs, the authors believe that a decrease in allogeneic donor exposures alone is sufficient reason to make SDPs the platelet

*Medical Director, Transfusion Service, University of Southern California (USCI University Hospital and Med- ical Director, USC Blood Donor Center Assistant Profes- sor of Pathology, USC tSenior Resident in Pathology, LAC+USC Medical Center :~LAC and USC Medical Center, PO Box 71, 1200 North State Street, Los Angeles, CA 90033, USA §Author for correspondence.

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component of choice at their insitu- tions. © 1997 Elsevier Science Ltd •

585

A basic tenet of the medical profession is to do no harm. Consequently, pro- tecting our patients from adverse effects of therapeutic interventions is a primary concern. Many steps in the blood col- lection, processing, and transfusion pro- cess are directed toward minimizing the risk of transfusion trasmitted infectious diseases, and central to that intention is limitation of the number of allogeneic blood donors to which a patient is exposed. This is a fundamental goal of transfusion safety programs such as perioperative autologous blood pro- grams, intraoperative autotransfusion programs, and hemodilution. 1,2 The transfusion services at the University of Southern California Health Sciences Campus (USC University Hospital, the Norris Cancer Hospital, and Los Angeles County+USC Medical Center) all routinely use single donor apher- esis platelets (SDPsJ rather than ran- dom donor platelets (RDPs) in an effort to minimize allogeneic expo- sure. RDPs are used only when SDPs are not available or for our very small patients (neonates/infants/small chil- dren) for whom a single RDP unit may provide a therapeutic dose. The USC Blood Center collects SDPs exclusively but never manufactures whole blood units into platelet concentrates. Although there are other safety, techni-

586 Transfus. Sci. Vol. 18, No. 4

cal, and medical-legal reasons to use SDPs, the authors believe that the decrease in allogeneic donor exposures alone is sufficient reason to make SDPs the platelet component of choice at USC. A single unit of SDPs constitutes a sin- gle adult "dose" of platelets. However, it takes 6-10 units of random donor pla- telets to constitute a usual "dose" of platelets for a full-sized adult. Thus, an adult dose of RDPs carries with it a potential risk of infectious disease transmission that is at least 600% greater than an equivalent dose of SDPs. For example, the possibility that an infectious disease will complicate the transfusion of six pooled RDPs is 1/5500 vs. 1/33,000 for the equivalent dose administered as SDPs. 3 However, the risk of the pooled RDPs may be even greater because apheresis donors are often repeat, multiply tested donors and are unlikely to be donating merely for the purpose of obtaining a free test result (such as HIV). Although we are unaware of a specific study that docu- ments an increased incidence of trans- fusion-related viral disease in patients transfused with RDPs, we believe that, like in a game of Russian roulette, increasing the number of bullets in the gun can only increase the odds of a bad outcome for the player. Additionally, some authors find the degree of bacter- ial contamination higher among RDPs when compared to SDPs. 4 However, an increased risk of bacterial contamina- tion for RDPs might actually reflect the longer average duration of storage of RDPs compared with SDPs, rather than an inherent problem with RDPs.

Proponents of RDPs might argue that the risk of transfusion-transmitted disease is currently quite low for the pathogens (of which we are aware) s and that to use SDPs unnecessarily increa- ses the cost of transfusion therapy. However, cost-effectiveness arguments may be viewed by the public as inap- propriate when dealing with the possi- bility of disease transmission. Witness the implementation of the HIV-p24 antigen blood donor screening test.

Despite extensive pre-implementation trials that demonstrated very little effi- cacy for interdicting HIV viremic but anti-HIV antibody negative donors, an assay to detect HIV-p24 antigen is now a required, blood donor-screening test. 6-s Autologous blood programs, which are still widely used, waste an alarming proportion of collected units and have been shown in several studies to provide little benefit compared to cost. Yet con- cemed lay people continue to demand access to this blood transfusion option. 9,1° Hence, use of RDPs or any other therapy that would increase a patient's exposure to allogeneic transfu- sions could be considered contrary to many of the current efforts to increase blood safety. Although cost effective- ness has become important in today's health care market, any decision that increases a patient's risk of an adverse outcome {i.e. exposure to transfusion- transmitted disease) based primarily on financial considerations is precarious if a safer, but equally effective, alternative therapy were widely available. Transfu- sion service directors could find it diffi- cult to explain why cost concerns were favored over safety.

At this time, SDPs are more expen- sive than RDPs in the Los Angeles metropolitan area. However, there has been an increase in the number of SDP products available in the Los Angeles area due to increased production at existing {and new) blood centers and at hospital collection facilities in the area. Increased importation of SDPs into the region has further increased the supply. Prices charged by some vendors have fallen modestly, and we expect that increased competition will pressure a further lowering of prices for SDPs in the near future. Spot prices are occa- sionally heavily discounted as excess, short-dated SDPs have become available from Northern Califomia and other regions. If a drop in the price of SDPs should become sustained, the use of RDPs (at least in Southern California) as a cost-savings strategy might become less convincing.

Single Donor Platelets vs Random Donor Platelets, Cost vs Sa[ety Considerations 587

In addition to safety considerations, transfusion services might prefer SDPs because they do not require technologist t ime for pooling, and require less t ime for inventory management, since each SDP is equivalent in dose to 6-10 RDPs. If fewer platelet products need to be processed, the chance of a clerical error should be reduced, and fewer regulatory and medical-legal complications might result. Furthermore, because SDPs do not require pooling, there is less chance of bacterial contamination, 4 which is a major concern of platelet products stored at room temperature.

SDPs platelets may now be collec- ted using a system that provides adequate leukodepletion without filtra- tion. ~1 Such methods can save the transfusion service the cost of a filter, save the time and training required to filter a component, and avoid the possi- bility of filter failure or of bacterial con- tamination secondary to using an open system.

SDPs are necessary for the patient who requires of HLA matched and crossmatch-compatible platelets, the demand for both of which may increase as heroic therapies become more com- monplace such as bone marrow and solid organ transplants. Increased SDP production, because of more routine, would expand the immediately avail- able inventory and, thus, improve the chance of locating a compatible unit within the region.

New apheresis technologies, such as the Haemonetics device {recently FDA approvedl will allow collection of an SDP concurrently with a red cell or plasma component. Collections of more than one blood component per donor would increase total efficiency and lower costs as only one nurse's time, one software set, and one battery of infectious disease tests would be required. If projections are accurate, this mult icomponent collection strategy may result in price reductions for SDPs.12,13

Although SDPs may be the compo- nent of choice for patients requiring

platelet transfusions at USC, there is still a place for the use of RDPs, parti- cularly when SDPs are not available or when tiny patients require platelet transfusions. In situations where there is strong evidence of alloimmunization to platelet transfusion, HLA matched or crossmatched platelets, although not always effective, would be components of choice. However, in urgent situations or other instances when these compo- nents are not available, use of RDPs may be empirically indicated using the rationale that if multiple donors are used, there is an increased chance that some of the transfused platelets may be compatible. The authors are not aware that the efficacy of this rational has been documented. RDPs also may be necessary due to shortages of SDPs.

From the perspective of the USC blood center, SDPs provide a product that is safer for patient use and more convenient to inventory than RDPs. As with a hospital transfusion service, the use of SDPs spares the blood center processing time, reduces the overall size of the inventory that must be main- tained, and reduces the potential for contamination that can occur with the manufacture of RDPs, especially if the blood center is expected to pool plate- lets for the transfusion services. Some blood centers pool and then leukocyte- deplete RDPs. Such a process adds an additional level of complexity when compared to methods that are available for leukodepletion of SDPs {i.e. SDPs containing less than one million leuko- cytes per container may be collected via automated apheresis technology using a closed system}. 11 For centers with blood irradiators, less technologist and irra- diator t ime is required when irradiating SDPs vs. an equivalent dose of RDPs because fewer components need to be processed.

In summary, SDPs are the platelet product of choice at our institutions mainly because their use decreases the number of allogeneic platelet products to which patients are exposed and thus avoids {or reduces} certain health,

588 Trans~s. Sci. Vol. 18, No. 4

medical-legal, and regulatory risks. Until it is shown that a pool of RDPs is as safe (dose per dose) as the apheresis product, the transfusion services at the University of Southern California (Nor- ris Cancer Hospital, USC University Hospital, and LAC+USC Medical Cen- ter) will continue to routinely use SDPs. However, if RDPs are shown to be equally safe as SDPs, and if the equiva- lent dose remains available at a lower cost, then the use of RDPs would be encouraged.

REFERENCES

1. Blais RE, Hadjipavlou AG, Shulman G: Efficacy of autotransfusion in spine sur- gery: Comparison of autotransfusion alone and with hemodilution and apheresis. Spine 1996; 21:2796-2800.

2. Petz DP, Swisher SN: Autologous, directed, and home transfusion pro- grams; hemodilution, in Clinical Prac- tice of Transfusion Medicine, 2nd edn, Chapter 14, p. 336 Churchill Living- stone, New York.

3. Schreiber GB, Dusch MP, Kleinman SH, Korelitz JJ: The risk of transfusion transmitted viral infections. N Engl J ivied 1996; 334:1685-1690.

4. Morrow JF, Braine HG, Kickler TS: Septic reactions to platelet transfusion: A persistent problem. J Am Med Assoc 1991; 266:555-558.

5. Williams AE, Thomson RA, Schreiber GB: Estimates of infectious disease risk

factors in US blood donors. J Am Med Assoc 1997; 277:967-972.

6. Le Pont F, Costagliola D, Rouzioux C, Valleron AJ: How much would the safety of blood transfusion be improved by including HIV-p24 antigen in the battery tests?. Transfusion 1995; 35:542-547.

7. AuBuchon JP, Birkmeyer JD, Busch MP: Cost effectiveness of expanded human immunodeficiency virus-testing proto- cols for donated blood. Transfusion 19977 37:45-51.

8. Sibrowski W, Wullenweber J: Risk of infection in hemotherapy. Infusions- therapie und Transfusionsmedizin 1994; 21 (Suppl 1):60--63.

9. Etchason J, Petz L, Keeler E: The cost effectiveness of preoperative autologous blood donations. New Engl J Med 1995; 332:719-724.

10. Domen R: Preoperative autologous blood donation: clinical, economic, and ethical issues. Cleve Clin J Med 1996; 63:295--300.

11. Foumel J-J, Zingsem J, Riggert J: A multicenter evaluation of the routine use of a new white cell-reduction apheresis system for collection of platelets. Transfusion 1997; 37:487- 492.

12. Valbonesi M, Frisoni R, Flofio G: Single- donor platelet concentrates produced along with packed red blood cells with the haemonetics MCS 3p: preliminary results. J Clin Apheresis 1994; 9:195- 199.

13. ABC Newsletter: FDA approves haemo- netics double red cell collection device. April 1997.