Blood collection and transfusion in the United States in 1997

BACKGROUND: Collections, processing, and transfusions of blood and blood components in the US in 1997 were measured and compared with 1994 and prior years. STUDY DESIGN AND METHODS: Questionnaires were returned by 2391 blood centers, AABB member hospitals, nonmember hospitals, and other facilities. Statistical procedures were used to verify that the sample was representative and to estimate national collections and utilization. RESULTS: The gross domestic blood supply in the US in 1997 was 12,602,000 units, 5.5 percent less than in 1994. It included 11,741,000 units of allogeneic community blood, 643,000 units of autologous blood, and 205,000 units of allogeneic-directed blood. Platelet transfusions amounted to 9,037,000 platelet concentrate equivalent units, of which 62.4 percent were apheresis packs. Compared with 1994, total platelet units transfused increased by 14.9 percent and single-donor platelet units transfused increased by 31.7 percent, whereas platelet concentrate transfusion declined by 3.8 percent. Transfusions of FFP increased by 26.6 percent compared with 1994. CONCLUSIONS: The margin of US allogeneic blood supply in excess of allogeneic transfusions in 1997 was 630,000 units, 5.4 percent of total allogeneic supply as compared with margins in prior years ranging between 9.3 and 10.9 percent. Although overall allogeneic available supply in 1994 was adequate to meet transfusion demand, the decrease in the margin between 1994 and 1997 is cause for concern. The rate of whole-blood collections in 1997 per 1000 members of the population aged 18 to 65 years was 12.6 percent lower than 1994. The RBC transfusion rate per 1000 members of the population in 1997 remained nearly the same as in 1994. However, the rates of platelet and of plasma transfusions both increased.     

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.     

Blood collection and transfusion in the United States in 2001

BACKGROUND: Collection, processing, and transfusion of blood and blood components in the United States in 2001 were measured and compared with prior years. STUDY DESIGN AND METHODS: The survey was completed by 1443 blood centers and hospitals. Statistical procedures were used to verify the representativeness of the sample and to estimate national totals. RESULTS: The total US blood supply in 2001 was 15,320,000 units (before testing), 10.4 percent greater than in 1999. It included 14,259,000 allogeneic units, 619,000 autologous units, and 273,000 red cell (RBC) units collected by apheresis. Transfusion of whole blood (WB) and RBCs increased by 12.2 percent to 13,898,000 units. Platelet (PLT) transfusions totaled 10,196,000 units, an increase of 12.6 percent in comparison with 1999. The use of single-donor apheresis PLTs increased by 26.0 percent to 7,582,000 PLT concentrate equivalent units. The use of PLTs from WB (PLT concentrates) continued a downtrend, declining 13.9 percent to 2,614,000. CONCLUSIONS: The margin between transfusion demand and the total allogeneic supply in 2001 was 1,162,000 units, 7.9 percent of supply. By comparison, the 1999 margin was 9.1 percent. The rate of blood collection per 1,000 donor-eligible population in 2001 was 8.9 percent higher than in 1999, due largely to additional donations following the September terrorist attacks. During the same period, however, the rate of transfusion per 1,000 total US population increased by 9.9 percent to 50.0 units, the highest in 15 years of measurement. The steady increase in demand continues to challenge the US blood community.     

Epidemiology of blood transfusion

BACKGROUND: Earlier investigations of the epidemiologic attributes of blood transfusion were not based on total community populations. To calculate incidence rates of the transfusion of blood and blood components in the general population and in age- and gender-specific groups, all residents of a United States county who received transfusion(s) from 1989 through 1992 were studied. STUDY DESIGN AND METHODS: The study was a prevalence survey (cross-sectional study) of a well-defined population at a specified time. RESULTS: There was no significant change in blood and blood component utilization from the beginning of 1989 through 1992. The incidence of red cell transfusion was 42.88 units per 1000 population per year in both men and women and varied from 12.08 units per 1000 population per year in those less than 41 years old to 245.24 units per 1000 population per year in the group aged more than 65. A random resident's probability of receiving transfusion(s) in any year was 0.89 percent (0.83% for men and 0.94% for women) and varied from 0.26 to 5.17 percent among the three age groups. The incidence of platelet and fresh-frozen plasma transfusion was 21.24 units per 1000 population per year and 8.64 units per 1000 population per year, respectively. CONCLUSION: Incidence rates of blood transfusion for "causal" planning of blood collections are presented here for the first time. The probability of receiving a transfusion of RBCs in any year rises by 20-fold from the rate in those less than 40 years old to that in those more than 65 years old, who receive 53.3 percent of the red cell units transfused.     

Blood collection and transfusion in the United States in 1999

BACKGROUND: Collection, processing, and transfusion of blood and blood components in the US in 1999 were measured and compared with prior years. STUDY DESIGN AND METHODS: Questionnaires were completed by 2040 blood centers and hospitals. Statistical procedures were used to verify the representativeness of the sample and to estimate national totals. RESULTS: The total US blood supply in 1999 was 13,876,000 units (before testing), 10.1 percent greater than in 1997. It included 13,109,000 allogeneic units, 651,000 autologous units, and 116,000 red cell (RBC) units collected by apheresis. Transfusion of whole blood and RBCs increased by 7.6 percent to 12,389,000 units. Platelet (PLT) transfusions totaled 9,052,000 PLT concentrate equivalent units, of which 66.5 percent were PLTs from apheresis. In comparison with 1997, the total number of PLT units transfused was unchanged, whereas single-donor PLT units transfused increased by 6.7 percent and the transfusion of PLTs from whole blood (PLT concentrates) declined by 10.6 percent (a difference of approximately 400,000 units in each case). CONCLUSIONS: The margin between transfusion demand and the total allogeneic supply in 1999 was 1,203,000 units, 9.1 percent of the supply. By comparison, the margin in 1997 was 7.2 percent, whereas in 1989 it was 13.8 percent. Similarly, the rate of blood collection in 1999 per 1000 population was 11.9 percent higher than the 1997 rate. During the same period, however, the rate of transfusion per 1000 population increased by 5.8 percent. Risk in the future lies primarily in the increasing demand for RBCs and further shrinkage of the supply-and-demand margin.     

Impact of the COVID-19 pandemic on blood donation and transfusions in the United States in 2020

Introduction

Reports have suggested the COVID-19 pandemic resulted in blood donation shortages and adverse impacts on the blood supply. Using data from the National Blood Collection and Utilization Survey (NBCUS), we quantified the pandemic's impact on red blood cell (RBC) and apheresis platelet collections and transfusions in the United States during year 2020.

Methods

The 2021 NBCUS survey instrument was modified to include certain blood collection and utilization variables for 2020. The survey was distributed to all US blood collection centers, all US hospitals performing ≥1000 surgeries annually, and a 40% random sample of hospitals performing 100–999 surgeries annually. Weighting and imputation were used to generate national estimates for whole blood and apheresis platelet donation; RBC and platelet transfusion; and convalescent plasma distribution.

Results

Whole blood collections were stable from 2019 (9,790,000 units; 95% CI: 9,320,000–10,261,000) to 2020 (9,738,000 units; 95% CI: 9,365,000–10,110,000). RBC transfusions decreased by 6.0%, from 10,852,000 units (95% CI: 10,444,000–11,259,000) in 2019 to 10,202,000 units (95% CI: 9,811,000–10,593,000) in 2020. Declines were steepest during March–April 2020, with transfusions subsequently rebounding. Apheresis platelet collections increased from 2,359,000 units (95% CI: 2,240,000–2,477,000) in 2019 to 2,408,000 units (95% CI: 2,288,000–2,528,000) in 2020. Apheresis platelet transfusions increased from 1,996,000 units (95% CI: 1,846,000–2,147,000) in 2019 to 2,057,000 units (95% CI: 1,902,000–2,211,000) in 2020.

Conclusion

The COVID-19 pandemic resulted in reduced blood donations and transfusions in some months during 2020 but only a minimal annualized decline compared with 2019.     

Blood collections by community blood centers, 1988 through 1992

BACKGROUND: The provision of a safe and sufficient supply of blood is critical to patient care. STUDY DESIGN AND METHODS: A survey was conducted of the blood collection activity of the 189 community blood centers operating in the United States from 1988 through 1992. Data were analyzed by source of the donation (allogeneic or autologous), by center's collection volume, and by geographic region. Total collection figures were compared to historical blood collection activity since 1970. RESULTS: A total of 12.31 million units of blood were collected in 1992, an increase of 2.6 percent over the total number of units collected in 1988. For the 5-year period (1988-1992), total collections increased at a compound annual growth rate of 0.6 percent. The collection of allogeneic blood units declined by 0.2 percent annually, while that of autologous units increased by 23.2 percent annually. Autologous blood units accounted for 5.7 percent of total collections in 1992. Nationally, 48 units were collected per 1000 people in 1992, although substantial geographic variation (range, 38–64 units/1000) was observed across nine US census regions. CONCLUSION: The data from this study provide evidence that the total supply of blood grew more slowly from 1988 through 1992 than in the years before 1988.     

Collection and transfusion of blood and blood components in the United States, 1989

To probe recent trends in transfusion practice and their effect on the adequacy of the national blood resource, transfusions and collections in the United States in 1989 were studied, by using data shared by the American Association of Blood Banks, the American Red Cross, and the Council of Community Blood Centers, together with results from a sample survey of the 3600 hospitals that were not members of the national organizations. Statistical methods were used to estimate national activities. The total US supply of blood in 1989 was 14,229,000 units, an increase of 1.2 percent over the supply in 1987. Red cell transfusions were 12,059,000 units. A total of 3,159,000 patients underwent transfusion with whole blood and/or red cells (mean, 3.8 units/patient). Preoperative autologous deposits of 655,000 units by 310,000 patients represented an increase of 65 percent over the level in 1987. However, only 356,000 units (54%) were transfused to the patients who preoperatively deposited them; of the remainder, 13,000 units were crossed over for transfusion to other patients, while 286,000 units were never used. Directed donations, 350,000 units, were provided for 130,000 intended recipients, but only 97,000 units (28%) were transfused to their intended recipients; of the balance, 59,000 units (17%) were crossed over and 194,000 units (55%) were never transfused. Total platelet transfusions were equivalent to 7,258,000 units in 1989, for an increase of 13.7 percent over totals in 1987.     

Changing patterns of blood transfusions in four sets of United States hospitals, 1980 to 1985

Annual transfusion activity between 1980 and 1985 was surveyed in four sets of United States (US) hospitals, which together accounted for 4.8 percent of the red cell (RBC) transfusions in the US in 1980. Total RBC transfusion rates (total RBCs transfused/1000 hospital admissions) increased between 1980 and 1982 but remained nearly constant between 1982 and 1985. Plasma transfusion dynamics followed a similar pattern, whereas the preoperative deposit of autologous blood by patients accelerated rapidly after 1982. These changes appear to reflect responses to the acquired immune deficiency syndrome epidemic. In contrast, total platelet transfusion rates grew by 76 percent during the 6-year period, approaching total RBC rates by 1985. This is the first reported evidence in such a large sample of transfusions that total RBC transfusion rates have moderated.     

The use of a chemiluminescence-linked universal bacterial ribosomal RNA gene probe and blood gas analysis for the rapid detection of bacterial contamination in white cell-reduced and nonreduced platelets

Because of the rising incidence of bacterial growth and septic platelet transfusions in aging units, platelet storage is currently limited in the United States to 5 days. This approved shelf life of platelets might be altered if methods were devised to rapidly detect infected units and/or to decrease the incidence of bacterially contaminated platelets. An investigation was conducted on the effect of a prototype blood collection system with an in-line filter for the production of white cell-reduced platelet-rich plasma on the growth of bacteria in platelets prepared from whole blood that had been inoculated with Staphylococcus epidermidis. Additional studies were conducted with a chemiluminescence-linked ribosomal RNA (rRNA) gene probe and with blood gas analysis to identify possible methods for the rapid detection of bacterial contamination. All units were followed for 9 days of storage. The filtration of the platelet-rich plasma resulted in an approximate 2 log10 reduction in white cells with an average loss of 6.7 percent of platelets. Filtration did not appear to alter bacterial growth. In all platelet units that supported growth, pO2 dropped to negligible values and pCO2 rose relative to culture-negative units. The changes were most sensitive and specific beyond 5 days of storage. The universal bacterial rRNA probe assay was able to detect S. epidermidis in concentrations as low as 1 × 10(3) colony-forming units per mL in some cases and reliably detected all units contaminated at a concentration of 1 × 10(4) colony-forming units per mL.(ABSTRACT TRUNCATED AT 250 WORDS)     

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.     

Pooled platelet concentrates provide a small benefit over single-donor platelets for patients with platelet refractoriness of any etiology

BackgroundAt our institution, patients with platelet refractoriness (of any etiology) are sometimes switched from apheresis platelets to pooled platelets before human leukocyte antigen (HLA)-matched units become available.Study design and methodsSeven patients were analyzed. Platelet counts were available from 57 single-unit transfusions (26 pooled, 31 apheresis). A mixed linear effects model was used and significance was determined using a likelihood ratio test.ResultsWhen analyzed as the only fixed effect in the model, the use of pooled versus single-donor units and time from transfusion to post-transfusion blood sampling each showed a significant effect on platelet count increments. A mixed linear effect model including both factors showed that transfusing a pooled unit correlated with a 4500±2000/µL greater platelet count increment compared with a single-donor unit, and an increase in time from transfusion to post-transfusion blood sampling lowered the platelet count increment by 300±100/µL per hour.ConclusionA small but potentially clinically relevant benefit was observed in transfusing pooled random-donor platelets compared with single-donor units for patients with platelet refractoriness (of any etiology).     

A prospective microbiologic surveillance program to detect and prevent the transfusion of bacterially contaminated platelets

After two patients received bacterially contaminated platelet transfusions, a prospective surveillance program was instituted to perform Gram staining and microbiologic culturing of platelets at the time of transfusion. In 12 months, 3141 random-donor platelet pools (prepared from 14,481 units) and 2476 single-donor apheresis units were cultured. All single-donor apheresis units were sterile, but 6 (0.19%) of the random-donor pools were found to be bacterially contaminated, with 1 unit of 5 in the pool being the source in each case. Contaminants were Staphylococcus epidermidis (4 cases), Bacillus cereus (1), and Staphylococcus aureus (1) at counts of 0.5 × 10(2) to 10(11) colony-forming units per mL in platelet pools and 10(3) to 10(13) colony-forming units per mL in source units. The contamination rate for units transfused at < or = 4 days (1.8/10,000) was significantly lower than that at 5 days (11.9/10,000; p < 0.05), as was the magnitude of contamination (p < 0.05). Use of the pretransfusion Gram stain on 4- and 5-day-old platelet pools was 100 percent sensitive (4/4 true positives) and 99.93 percent specific (1 false positive) in detecting contaminated pools. These data define the extent and magnitude of platelet bacterial contamination and demonstrate the efficacy of the pretransfusion Gram stain on platelet units stored for 4 and 5 days in preventing the transfusion of heavily contaminated units. It is concluded that the risk of platelet contamination is related to the duration of component storage.(ABSTRACT TRUNCATED AT 250 WORDS)     

Absence of D alloimmunization in D- pediatric oncology patients receiving D-incompatible single-donor platelets

BACKGROUND: Guidelines are lacking for prophylaxis against D alloimmunization after D-incompatible platelet transfusion. A rational basis for the application of prophylaxis would be beneficial for institutions in which inventory constraints demand the administration of large numbers of D-incompatible platelets. STUDY DESIGN AND METHODS: A retrospective analysis was performed of all D-incompatible platelet transfusions administered at a pediatric research hospital over a 1.5-year period. Patients exclusively received single-donor WBC-reduced platelets and did not receive RhIg immunoprophylaxis. Numbers, source, ABO type, duration of serologic follow-up, and level of RBC contamination of D-incompatible transfusions were analyzed. All positive D serologies in the institution over a 3.5-year period were examined to determine cause and potential association with platelet transfusion. RESULTS: Thirty-five patients not receiving bone marrow transplant and seven bone marrow transplant patients received 490 and 255 D-incompatible transfusions, respectively, over 1.5 years. Patients had various diagnoses, predominantly malignancies. Seventy-nine percent of D-incompatible transfusions were ABO compatible. An estimated 2300 incompatible transfusions were performed over 3.5 years. No case of D alloimmunization was detected. CONCLUSIONS: D immunoprophylaxis is generally unnecessary in pediatric oncology patients receiving D-incompatible, WBC-reduced, single-donor platelets not visibly contaminated by RBCs. Further studies to validate these observations in the pediatric population and to extend them to other population groups are warranted.     

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.     

Febrile reactions after platelet transfusion: the effect of single versus multiple donors

Febrile reactions to platelet transfusions are a common problem. The platelet transfusion records from a 30-month period were analyzed to determine 1) when reactions occur in a transfusion sequence; 2) how frequently they recur; and 3) whether the choice of multiple-donor (pooled concentrates) or single-donor components (unmatched apheresis and HLA-compatible apheresis platelets) affected the reaction rate. Overall, 18.7 percent of all patients receiving platelets experienced reactions. A subset of 85 patients, who began platelet support with unmodified components during the study interval, were analyzed in detail. This group received 1204 unmodified transfusions (mean, 14.2/patient), which were associated with 171 reactions (per-transfusion reaction rate, 14.2%). Despite a higher mean white cell content, the transfusion of 438 unmatched single-donor platelets (10.84 x 10(8) white cells, 8.4% reaction rate) resulted in reactions significantly less often than did that of 583 pooled concentrates (8.53 x 10(8) white cells, 21.4% reaction rate) (p less than 0.001). The rate of reaction to HLA-compatible platelets (9/183 transfusions, 4.9%) was not significantly different from that to unmatched single-donor platelets. The use of platelet components from one donor, as opposed to multiple donors, may provide an effective means of reducing the incidence of febrile reactions.     

Possible transmission of human herpesvirus-8 by blood transfusion in a historical United States cohort

BACKGROUND: Transmission of human herpesvirus-8 (HHV-8) by blood transfusion in the United States appears plausible but has not been demonstrated. The objective of this study was to evaluate evidence of HHV-8 transmission via blood transfusion. STUDY DESIGN AND METHODS: Serum specimens were collected before and 6 months after surgery from 406 patients who enrolled in the Frequency of Agents Communicable by Transfusion study (FACTS) in Baltimore, Maryland, from 1986 to 1990. The change in HHV-8 serostatus was measured by a lytic-antigen immunofluorescence assay. RESULTS: Of the 284 patients who were initially HHV-8-seronegative and who received transfusions, 2 seroconverted, 1 with a postsurgery antibody titer of 1:160 and the other with a titer of 1:1280. These patients received 12 and 13 units of blood, respectively. None of the HHV-8-seronegative patients who did not receive transfusions seroconverted. If seroconversion was caused by transfused blood, the transmission risk per transfused component was 0.082 percent. CONCLUSIONS: This is the first report suggesting transmission of HHV-8 via blood components in the United States. Because linked donor specimens were not available, other routes of transmission cannot be excluded; however, the evidence is consistent with infection being caused by transfusion. Future studies should include contemporary US populations with linked donor specimens and populations at higher risk for HHV-8 infection.     

Single-donor platelets reduce the risk of septic platelet transfusion reactions

BACKGROUND: Septic platelet transfusion reactions (SPTRs) are the most common, serious risk of transfusion. Because SPTRs result from donor skin flora or asymptomatic bacteremia, the use of single-donor platelets (SDPs) has been proposed to reduce the risk of SPTRs from the risks with pools of platelet concentrates (PCs). STUDY DESIGN AND METHODS: Beginning in 1986, all febrile transfusion reactions were evaluated by culture of the platelet bag. Confirmed SPTRs were identified by isolation of the same bacteria from the bag and the patient's blood or by positive Gram's stain of the bag that confirmed a positive platelet culture. In 1987, a program to minimize PC use in favor of SDP use was initiated as a means of reducing SPTRs. RESULTS: In 12 years, the use of SDPs increased from 51.7 percent to 99.4 percent of all platelet transfusions at one institution. SPTRs fell from three events in 1 year to the current rate of one event per year. The incidence of SPTRs decreased from 1 in 4,818 transfusions to 1 in 15,098 transfusions. The rate of SPTRs due to PCs was 5.39 times higher than that of SPTRs due to SDPs (95% CI, 1.89,12.9). CONCLUSION: The use of SDPs is a simple means of reducing SPTRs. Other measures such as sterilization will be required to eliminate all SPTRs.     

Evaluation of a centrifugal blood cell processor for washing platelet concentrates

A semiautomated saline wash procedure using a blood cell processor was evaluated as a technique for removing plasma from platelet concentrates. In vitro studies demonstrated 92 to 99.6 percent (mean, 96%) removal of total plasma protein (n = 30) with 84 to 97 percent (mean, 90.8%) platelet recovery (n = 28) in post-wash units. Post-wash pH values changed by +0.2 to -0.86 (mean, -0.47) (n = 30); the level of recovery from hypotonic shock was 69 to 97 percent (mean, 86%) (n = 11) of pre-wash units; weighted morphology scores decreased from a mean of 248 to 223 (n = 9). Aggregation response to arachidonic acid, collagen, and adenosine diphosphate plus epinephrine showed essentially no change following the wash procedure, and electron microscopy demonstrated slight morphologic alteration. Autologous platelets labeled with indium-111 demonstrated 43 +/- 20 percent recovery (n = 11) for washed units, compared to 41 +/- 10 percent for control unwashed units (n = 5); mean survivals were 140 +/- 41 hours (n = 11) for washed platelets and 185 +/- 28 hours for unwashed units (n = 5). Thirteen alloimmunized patients receiving 55 washed platelet concentrates demonstrated a mean 1- to 4-hour corrected count increment of 3.99 X 10(3) per microliter, compared to 3.02 X 10(3) per microliter for 77 unwashed platelet units given to the same patients. This study documents that platelet concentrates maintain viability and efficacy following a semiautomated saline wash method using the Cobe 2991 Blood Cell Processor, a technique that may be helpful for patients who require plasma-depleted platelet transfusions.