Blood donor-, apheresis-, and transfusion-related activities: results of the 1991 American Association of Blood Banks Institutional Membership Questionnaire

Approximately 2154 regional blood centers and hospital-based blood banks and transfusion services responded to the 1991 American Association of Blood Banks Institutional Membership Questionnaire that elicited data from 1990. Information from 2144 institutions was considered valid. Questionnaire topics were donor blood collections, hemapheresis, perioperative cell salvage, component usage, and transfusion-associated diseases. Institutional members reported collecting 9.3 million units, of which 90.9 percent were for allogeneic use in the community, 6.0 percent were for autologous use, and 3.1 percent were directed donations. The percentage of directed-donor units that were crossed over for allogeneic use (51%) was greater than the percentage of units transfused to the designated patient (49%). Only 12.5 percent of institutions reported obtaining specific consent for transfusion. Of the 15.4 million transfused blood components, 8.5 million were red cells, 4.1 million were platelets, 1.8 million were fresh-frozen plasma, and 0.9 million were cryoprecipitate. There were 1263 reported cases of transfusion-associated hepatitis. Approximately 44 percent of the patients who were tested proved positive for hepatitis B surface antigen, and 80 percent of the patients who were tested proved positive for antibody to hepatitis C. The questionnaire's aggregate results can be used to assess current patterns of blood donation and transfusion activities.     

Blood donation and transfusion practices: the 1990 American Association of Blood Banks Institutional Membership Questionnaire

Responses to the 1990 American Association of Blood Banks (AABB) Institutional Membership Questionnaire were submitted by 2126 regional blood centers, hospital-based blood banks, and transfusion facilities. Data from 2117 of these facilities were considered to be valid. The questionnaire included information on blood donor demographics, number of units collected, and collection procedures; services performed; usage of blood components; and transfusion-transmitted diseases reported during 1989. Institutional members collected 7.4 million whole blood units, of which 90.8 percent were donated for allogeneic use, 6.0 percent were donated for autologous use, and 3.2 percent were donated for directed use. Approximately 630,546 allogeneic and directed-use blood donors were deferred, most often for low hemoglobin or hematocrit values. Approximately 225,205 full allogeneic and directed-donor units were discarded, primarily for elevated alanine aminotransferase levels or the presence of hepatitis B core antibody. The 14.3 million transfused components included 56.7 percent red cell-containing components, 27.4 percent platelets, 11 percent fresh-frozen plasma, and 4.8 percent cryoprecipitate. Institutional members reported 1397 cases of transfusion-associated hepatitis. In this group, 921 patients were tested for hepatitis B surface antigen after the transfusion; 339 (36.8%) were found to be hepatitis B surface antigen positive. The AABB Institutional Questionnaire results provide recent data on blood donor and transfusion-related activities that are vital to the evaluation of current transfusion medicine practices.     

Providing ABO-identical platelets and cryoprecipitate to (almost) all patients: approach, logistics, and associated decreases in transfusion reaction and red blood cell alloimmunization incidence

BACKGROUND: There are multiple benefits to transfusing only ABO‐identical blood components. Historically our institution routinely transfused ABO‐nonidentical platelets (PLTs) and cryoprecipitate to surgical patients. In April 2005, we implemented a policy of transfusing only ABO‐identical components whenever feasible, regardless of outdating or logistic considerations. STUDY DESIGN AND METHODS: Technical staff closely monitored product usage and adjusted blood center orders based on recent utilization and planned transfusions. When unable to provide ABO‐identical PLTs, ABO‐compatible PLTs were washed to remove incompatible plasma. Data on outdating were collected for 18 months before and after implementation. We compared transfusion reaction and red blood cell (RBC) alloimmunization incidence for 4 years preceding (2001‐2004) and subsequent (2006‐2009) to implementation. RESULTS: In the year after implementation, only 11 of 410 surgical patients received ABO‐nonidentical PLTs (2.7%). There was a 5.6% increase in outdating of PLTs. Transfusing ABO‐identical components was associated with significant reductions in febrile (?46%; 8.0 to 4.3 per 10,000 components; p < 0.0001) and allergic transfusion reactions (?23%; from 7.0 to 5.4 per 10,000 components; p = 0.025). A progressive reduction in de novo RBC alloimmunization incidence also occurred (?50% by 2009; p = 0.03). CONCLUSIONS: Providing ABO‐identical PLTs to almost all patients was feasible in our setting by changing ordering and inventorying procedures and making the ABO‐identical policy a staff priority. Unexpected and striking reductions in febrile and allergic reactions and RBC alloimmunization were observed, of uncertain causal relationship to this ABO policy change, which will require further study.     

Blood and bombs: the demand and use of blood following the London Bombings of 7 July 2005--a retrospective review

Mass casualty events (MCE) present health systems with a sudden demand on key services. The overall objective of this study was to describe the experience of the National Blood Service (NBS) following the largest UK MCE in recent times. Data was collated from the NBS database and directly from the hospitals involved. All data was collected immediately following the event and included: all blood components requested, issued and transfused in relation to the bombings, blood stock levels at the time and the injury profiles of the casualties transfused. The total NBS order from hospitals for the event was 1455 units of blood components. All requests were fulfilled, this included: 978 units of red cells (RC), 36 doses of platelets, 141 units of fresh frozen plasma (FFP) and 300 doses of cryoprecipitate. The amount of blood ordered was three times that initially used and the total number of RC transfused in treating all victims from admission to discharge was approximately 440 units. The greatest use of blood components was for those casualties who had sustained traumatic amputations amongst their injury profile. Published data with which to compare these results is lacking, although the RC use was similar to the initial mean individual usage described in previous military and civilian bombings. The overall implication for any blood service remains, there is now likely to be a far greater demand for plasma, platelets and cryoprecipitate in any future incidents involving victims suffering major haemorrhage.     

Collection and transfusion of blood and blood components in the United States, 1992

BACKGROUND: Studies were conducted to measure the state of the United States' national blood resource in 1992 and changes therein from 1989. STUDY DESIGN AND METHODS: With data supplied by the American Red Cross and the American Association of Blood Banks, as well as data from a stratified random-sample survey of 3350 non-American Association of Blood Banks hospitals, statistical methods were applied to estimate national blood activities in 1992. RESULTS: The total US blood supply in 1992 was 13,794,000 units, a decrease of 3.1 percent from 1989. Some 11,307,000 red cell units were transfused to 3,772,000 patients, an average of 3.0 units per transfused patient. Preoperative autologous blood deposits totaled 1,117,000 units, a 70-percent increase over 1989. Of this number, 566,000 units (50.7%) were transfused, 5,000 (4.4%) transferred to the allogeneic supply, and 546,000 (48.9%) discarded. Of 436,000 directed-donation units, 136,000 (31.2%) were transfused, 57,000 (13.1%) transferred to allogeneic supply, and 243,000 (55.7%) discarded. The total allogeneic blood supply, including imports, decreased by 7.4 percent from 1989, and allogeneic blood transfusions, including those to children, decreased by 8.6 percent. Over 8,300,000 platelet units were transfused; of these, some 3,600,000 were apheresis platelets. In addition, 2,255,000 units of plasma and 939,000 units of cryoprecipitate were transfused. CONCLUSION: While the US blood supply was adequate for transfusion needs in 1992, blood collections and red cell transfusions had decreased substantially since 1989.     

Summary of the AABB Interorganizational Task Force on Bacterial Contamination of Platelets: Fall 2004 impact survey

BACKGROUND: New voluntary standards in the United States regarding bacterial contamination of platelets (PLTs) led to the formation of the AABB Interorganizational Task Force on Bacterial Contamination of Platelets. This article summarizes a survey conducted by the Task Force to assess the impact of bacterial detection. STUDY DESIGN AND METHODS: An Internet-based survey of AABB member institutions was conducted from September 17, 2004, to October 1, 2004. The survey was designed principally to assess PLT usage, supply, and outdating and the currently used bacteria detection methods. RESULTS: Of 900 facilities surveyed, 350 responded (38%). These facilities collected approximately 43.3 and 65.9 percent and transfused approximately 19.1 and 22.2 percent of the whole blood-derived PLT concentrates (WBPCs) and apheresis PLTs in the United States, respectively. Most facilities (64-91%) indicated that their ability to provide PLTs for transfusion had not been affected. Approximately half (50-57.1%) indicated no changes in their PLT inventory. Two-thirds (66-68%) indicated no increased PLT outdating. More than 90 percent of apheresis PLTs are tested with a culture-based method, whereas WBPCs are tested with a variety of methods (mostly non-culture-based) resulting in a 4.6-fold decrease in the confirmed positive detection rate compared with apheresis PLTs (p < 0.001). CONCLUSION: After the implementation of AABB Standard 5.1.5.1, the majority of facilities responding to this survey experienced no (or modest) impact on PLT availability or outdating. Nevertheless, a substantial portion of facilities experienced both increased outdating and decreased availability. Some facilities were greatly impacted. Based on the data gathered, it is impossible to conclude whether such shortages resulted from production or distribution problems or were due to decreased shelf life and increased outdates.     

Continued stabilization of blood collections and transfusions in the United States: Findings from the 2021 National Blood Collection and Utilization Survey

Background

National Blood Collection and Utilization Surveys (NBCUS) have reported decreases in U.S. blood collections and transfusions since 2008. The declines began to stabilize in 2015–2017, with a subsequent increase in transfusions in 2019. Data from the 2021 NBCUS were analyzed to understand the current dynamics of blood collection and use in the United States.

Methods

In March 2022, all community-based (53) and hospital-based (83) blood collection centers, a randomly selected 40% of transfusing hospitals performing 100–999 annual inpatient surgeries, and all transfusing hospitals performing ≥1000 annual inpatient surgeries were sent a 2021 NBCUS survey to ascertain blood collection and transfusion data. Responses were compiled, and national estimates were calculated for the number of units of blood and blood components collected, distributed, transfused, and outdated in 2021. Weighting and imputation were applied to account for non-responses and missing data, respectively.

Results

Survey response rates were 92.5% (49/53) for community-based blood centers, 74.7% (62/83) for hospital-based blood centers, and 76.3% (2102/2754) for transfusing hospitals. Overall, 11,784,000 (95% confidence interval [CI], 11,392,000–12,177,000) whole blood and apheresis red blood cell (RBC) units were collected in 2021, a 1.7% increase from 2019; 10,764,000 (95% CI, 10,357,000–11,171,000) whole blood-derived and apheresis RBC units were transfused, a 0.8% decrease. Total platelet units distributed increased by 0.8%; platelet units transfused decreased by 3.0%; plasma units distributed increased by 16.2%; and plasma units transfused increased by 1.4%.

Discussion

The 2021 NBCUS findings demonstrate a stabilization in U.S. blood collections and transfusions, suggesting a plateau has been reached for both.     

Current issues in transfusion therapy. 1. Risks of infection

Parasitic, bacterial, and viral infections may all be associated with transfusion of whole blood and components, including packed red blood cells, platelets, fresh-frozen plasma, and cryoprecipitate. Proper collection and storage techniques, careful donor selection, and laboratory screening of donor blood for evidence of syphilis, hepatitis B, and human immunodeficiency virus (HIV) infection form the basis for prevention of transfusion-transmitted infections. Viral hepatitis, notably non-A non-B hepatitis, is the most frequent infectious risk of transfusion in the United States today. The risk of HIV infection is very low because of voluntary donor self-deferral and screening of donated blood for evidence of the infection.     

Frequency and clinical characteristics of allergic transfusion reactions in children

Allergic transfusion reactions (ATRs)are a common form of acute transfusion reaction. It was aimed to determine the clinical characteristics and frequency of ATRs in children. This study included children who were transfused with red cell concentrate (RCC), fresh-frozen plasma (FFP), platelet concentrates(PC), apheresis granulocyte, and cryoprecipitate.The patients’ sociodemographic characteristics, the blood product that caused the reaction, the type and timing of the reaction, the patient’s age at time of reaction and their diagnosis, follow-up period, and clinical data were recorded. A total of 89703 bags of blood products were transfused to 4193 children.Two hundred eleven acute transfusion-related reactions occurred in 157 (3.74%) patients.Of these, 125 reactions (59%) were allergic. ATR occurred in 125 of 89703 infusions (0.14%).The median age of patients was 9.99 years (IQR:4.67-14.38) and ATRs occurred at a median of 30 minutes into the transfusion. Eighteen (18%) of the patients also had a history of drug reaction.When the blood products that caused ATRs were examined, 43(34.5%) occurred with apheresis and single-donor PC, 37(29.6%) with FFP, 32 (25.6%) with RCC, 10(8%) with pooled PC, 2(1.6%) with cryoprecipitate, 1(0.8%) with apheresis granulocyte.Ninety-nine(79%) of the reactions were minor allergic reactions and 26(21%) were anaphylaxis.Compared to minor allergic reactions, the proportion of PCs was statistically higher in anaphylaxis(p=0.02). Patients receiving PC should be monitored more carefully during the first half hour of transfusion. In addition, approximately one-fifth of the patients who developed ATR also had a history of drug reaction. Patients with previous reactions to drugs may be more likely to have ATR.     

Evaluation of platelets prepared by apheresis and stored for 5 days. In vitro and in vivo studies

To evaluate the effect of storage on apheresis platelets collected with a closed-system blood cell separator, an in vitro investigation was performed, with measurements of pH, lactate, ATP, the ratio of ATP to the total adenine nucleotide content, and adenylate kinase. Unmodified apheresis platelets and apheresis platelets with plasma added were compared with conventional platelets stored in PL-1240 or PL-732 plastic containers. During 6 days of storage, there were similar changes in all variables with one exception: the extracellular activity of adenylate kinase was lower in apheresis platelets with plasma than in the other three groups (p less than 0.01). In vivo studies were carried out with 111Indium-labeled autologous platelets in eight volunteers. Apheresis platelets with 100 mL of plasma added were stored in two 1000-mL containers (PL-732) at 22 degrees C during agitation. Platelets from one of the containers were labeled with 111Indium and transfused into the volunteer within 24 hours. Platelets from the other container were labeled after 5 days of storage and transfused into the same donor. There were no significant differences between apheresis platelets stored for 1 day and those stored for 5 days: the mean percentage of recovery was 58.4 and 57.6 percent, t1/2 was 69 and 67 hours, and the survival time was 5.5 and 5.6 days, respectively.     

Blood inventory distribution by type in a total supply system

Review of blood distribution by blood type in 37 hospitals served by one blood center revealed that bloods collected from a random population of donors and transfused to a random population of recipients show a normal distribution of types. However, 35 per cent of donors who are drawn in the hospitals are Rh-negative and 19 per cent of bloods returned outdated are Rh-negative. Examination of the data indicates the low-frequency blood types are stored out of proportion to their utilization rate and are more likely to be lost through outdating. Alternative solutions are suggested.     

Repeat ABO-incompatible platelet transfusions leading to haemolytic transfusion reaction

A 65-year-old woman, blood group A RhD positive, who had completed her first course of induction chemotherapy for acute myeloid leukaemia was transfused with apheresis platelets over a number of days. On three occasions she received group O RhD positive units, which had been screened and found not to contain high-titre anti-A,B isoagglutinins. Following the third unit, she developed a haemolytic transfusion reaction and died soon thereafter. This has led to change in policy of the supplying centre in testing for high-titre anti-A,B isoagglutinins. Blood group O apheresis platelets and fresh-frozen plasma units are now labelled as high titre with a cut-off of 1/50 as compared to the previous cut-off of 1/100 for anti-A,B isoagglutinins. A universal approach to testing donations for high-titre anti-A,B isoagglutinins, better compliance of guidelines and monitoring of patients is necessary.     

The introduction of 7-day platelets: a university hospital experience

INTRODUCTION: Recently, the FDA approved the Post Approval Surveillance Study of Platelet Outcomes, Release Tested protocol which allows participating institutions to utilize 7 day platelets following guidelines. As one of the first hospitals to implement a 7-day protocol, we reviewed our hospital experience with 7-day Gambro apheresis platelets to determine the impact on inventory. METHODS: A review of apheresis platelet transfusions and outdate records was performed. Data were collected prospectively from March to August 2006. This data were compared with a retrospective review for the same time period in 2005. RESULTS: For the 1,503 platelets transfused from March-August 2005, the mean day of issue was 3.44 (SD = 1.060). During the same time period of 2006, 1,688 platelets were transfused with a mean day of issue of 4.02 (SD = 1.083). This difference was statistically significant (P < 0.001). The outdate rate dropped from 2.9% (44/1,547) to 1.3% (22/1,710, P < 0.001). During the study period, approximately 59.7% of the platelets were 7-day platelets. DISCUSSION: Over the 6-month period, we noted a decrease in outdates from 2.9% to 1.3%. There was a shift toward older platelets (from a mean of day 3.4 to day 4). During the study period, 139 platelets were transfused on days 6 or 7 of storage. Overall, the implementation of 7-day platelets in a university hospital setting was easily accomplished and has resulted in benefits to our institution by decreasing our outdate rate and to our patients by providing an additional 139 days 6 and 7 apheresis platelets with a potential cost savings of $78,952 (over the 6-month study).     

Cryoprecipitate use in 25 Canadian hospitals: commonly used outside of the published guidelines

BACKGROUND: Canadian Blood Services' disposition reports suggested considerable variation in cryoprecipitate use and prompted this national audit. STUDY DESIGN AND METHODS: Thirty‐one institutions were invited to participate in a 2‐month audit. Patient information and relevant laboratory and transfusion data were collected. Cryoprecipitate transfusions were categorized as appropriate if a fibrinogen level (taken 6 hr before/after transfusion) was not more than 1.0 g per L and inappropriate if the pretransfusion fibrinogen level was more than 1.0 g per L and posttransfusion fibrinogen level was more than 1.0 g per L or not performed. Appropriateness was categorized as undetermined if the pretransfusion fibrinogen level was not performed and the posttransfusion fibrinogen level was more than 1.0 g per L or not performed. RESULTS: Overall, 25 of 31 invited hospitals agreed to participate. A total of 4370 units of cryoprecipitate were transfused in 603 events to 453 patients representing 62 percent of cryoprecipitate issued to hospitals during the time period. Comparison of the number of units of cryoprecipitate per 100 units of red blood cells (RBCs) transfused by each institution showed significant variation in practice (mean, 9 per 100 RBCs; range, 2 to 27 units). The single most common indication for cryoprecipitate was cardiac surgery (45.4% of events). Overall, 24 percent of cryoprecipitate transfusions were considered to be appropriate (pretransfusion fibrinogen level ≤1 g/L in 19% and posttransfusion fibrinogen level ≤1.0 g/L in another 5%), 34 percent were inappropriate, and in 42 percent appropriateness could not be determined. CONCLUSION: A 2‐month audit of cryoprecipitate use in Canada revealed that the majority of cryoprecipitate use in Canada is not in accordance with published guidelines.     

Experience of a combined apheresis, blood collection, and blood transfusion unit in a large tertiary care medical center

The Barnes Hospital Apheresis Blood Collection and Blood Transfusion Unit is part of Barns Hospital Blood Bank. Because of its size and complexity, we report our experience which may be useful to administrators and physicians involved in the planning or management of similar services. From 1985 through 1988 we collected platelets from 1,976 different donors, the majority of which (87%) were community donors. Sixty-nine percent of 1,976 donors donated in 1988 an average of 4.9 times. Of 6,568 apheresis products collected. 1.1% were discarded because of positive screening tests and 0.7% were discarded because of outdating or presence of fibrin clot. In 1988 a total of nine cell separators were used. All donor apheresis were done with seven blood separators, and on average a separator produced an apheresis product every 4.5 worked hours. All therapeutic apheresis (338) were done on two separators. Most of them (88%) were performed during work hours. In 1988 donor and therapeutic apheresis were done by 17 1/2 full-time employees (FTEs) during work hours. Considering the Workload Unit Value per procedure given by the College of American Pathologists (CAP) and that each FTE worked 1,864 hours per year, the worked hour productivity for donor and therapeutic apheresis was 78.2%. Blood collections, therapeutic bleeds, and outpatient transfusions (1,127, 114 and 1,745 respectively) were accomplished by two FTEs, for a worked hour productivity of 35.5%. Because 95.1% of total worked units was produced by efficient donor and therapeutic apheresis activities, overall efficiency remained high at 73.8%.     

Inventory management in Sydney Public Hospital Blood Banks

SUMMARY. Monitoring the outdating of donated units is one way of assessing the efficiency of blood usage. Inventory management in public hospital blood banks in Sydney was reviewed with the aim of determining factors which lead to the outdating of donor blood. Factors which correlated significantly with increased outdating in hospitals included absence of an effective hospital transfusion committee; high ratio of average inventory: units transfused; fewer than three routine deliveries from the BTS per day; increased time taken for delivery of urgent products; CT values greater than 2: 1; premature performance of the crossmatch and prolonged crossmatching holding time. Hospitals were informed of the initial audit results and were alerted to the factors contributing to excessive outdating. They received monthly feedback of individual outdating results compared with overall outdating. After 6 months there was a significant reduction in overall outdating from 5.0 to 0.9% ( P < 0.05), which has been maintained for a further 12 months. Changes in inventory management associated with an improvement in overall outdating included: changes in crossmatching practice which increase the effective shelf-life of blood, knowledge of when blood was due to outdate and effective stock rotation.     

Blood use in liver transplantation

During the first 5 years (1981-1985) of the liver transplantation program in Pittsburgh, a total (preoperative, intraoperative, and postoperative) of 18,668 packed red cell units, 23,627 fresh-frozen plasma units, 20,590 platelet units, and 4241 cryoprecipitate units was transfused for the procedures. This represents 3 to 9 percent of the total of blood products supplied by the Central Blood Bank to its 32 member hospitals. Six hundred thirty-six (636) transplants were performed on 485 patients in two hospitals: the Presbyterian University Hospital (564 beds) and Children's Hospital of Pittsburgh (236 beds). All of the blood components used in the operations were procured and released by the Central Blood Bank. This report describes some of these findings.     

Strategies for the avoidance of bacterial contamination of blood components

Gram staining and bacterial culturing methods were used to determine the incidence of bacterial contamination of cellular blood components at the time of transfusion reactions. Over a 5-year period, 2208 (4.3%) of 51,278 transfusions were complicated by reactions. Overall bacterial contamination occurred in 5 (0.03%) of 17,928 transfusions of single- donor apheresis platelets, 1 (0.14%) of 712 transfusions of pooled random-donor platelet concentrates, 1 (0.003%) of 31,385 transfusions of red cells, and 0 of 1253 transfusions of fresh-frozen plasma. Gram staining done at the time of positive cultures was positive in three of six cases. Although six of seven recipients of contaminated components suffered no clinical sequelae, contaminated transfusions may have been a contributing cause of death in one case. Attempts were made to avoid the transfusion of contaminated cellular blood components by performing routine bacterial cultures: 0 of 341 quality control cultures were positive. To avoid the transfusion of contaminated platelets by identifying bacteria, Gram staining was performed in all single-donor apheresis platelet units collected on open systems and daily in platelets stored > 48 hours: 8 (0.15%) of 5334 smears done on 3829 platelet units were interpreted as positive, and those units were not transfused, but only two of eight units were culture positive. These studies suggest that bacterial contamination can result in adverse clinical sequelae in transfusion recipients and that both culturing and Gram staining are poor methods of screening for contaminated units. More sensitive and specific methods of generalized screening for bacterial contamination are needed.     

Autologous transfusion. A safe alternative for the 1990s.

Autologous transfusion is a safe and affordable alternative to the traditional use of homologous blood. Many persons who would not ordinarily meet the criteria for homologous or directed donation can be autologous donors. The use of autologous blood ensures that the patient will not contract AIDS or hepatitis from transfused blood products. Many community hospitals have autologous blood programs, which allow them to draw, store, and reinfuse blood all under one roof.     

Determinants of red cell, platelet, plasma, and cryoprecipitate transfusions during coronary artery bypass graft surgery: the Collaborative Hospital Transfusion Study

BACKGROUND: Very little is known about the determinants of blood transfusions in patients undergoing coronary artery bypass graft surgery. STUDY DESIGN AND METHODS: To identify factors that influenced the transfusion of red cells, platelets, plasma, and cryoprecipitate, statistical methods were used to study 2476 consecutive diagnosis- related group 106 and 107 patients in five teaching hospitals who underwent coronary artery bypass surgery between January 1, 1992, and June 30, 1993. RESULTS: The likelihood of red cell transfusion was significantly associated with 10 preoperative factors: 1) admission hematocrit, 2) the patient's age, 3) the patient's gender, 4) previous coronary artery bypass surgery, 5) active tobacco use, 6) catheterization during the same admission, 7) coagulation defects, 8) insulin-dependent diabetes with renal or circulatory manifestations, 9) first treatment of new episode of transmural myocardial infarction, and 10) severe clinical complications. Platelet and/or plasma transfusions were strongly associated with the dose of red cells transfused. Transfusion requirements and other in-hospital outcomes were associated with patient characteristics, surgical procedure (reoperation vs. primary procedure), and the conduits used for revascularization (venous graft only, venous and internal mammary artery graft, or internal mammary artery graft only). Blood resource use and donor exposures were evaluated with respect to the risk to patients of contracting hepatitis C virus and human immunodeficiency virus infections. CONCLUSION: The classification of coronary artery bypass graft patients on the basis of attributes known preoperatively and by conduits used yields subsets of patients with distinctly different transfusion requirements and in- hospital outcomes.