White particulate matter found in blood collection bags consist of platelets and leukocytes

BACKGROUND: In late January 2003, some blood centers and hospitals throughout the US voluntarily sus-pended the use of some RBC and plasma units for trans-fusion due to the presence of unknown white particulate matter (WPM) in these units. To better understand the WPM phenomena, a number of technologies were used to establish the nature of the particulates observed in Terumo Collection sets. STUDY DESIGN AND METHODS: All AS-5 nonleuko-reduced RBCs and plasma units were visually inspected for WPM by placing the bags on a flat counter, undisturbed, for approximately 10 minutes and then perform-ing a visual examination for particles. Particles were isolated and placed on microscope slides or in plastic tubes for further analysis. Electron microscopy, bright field microscopy, differential interference contrast microscopy, infrared spectroscopy, and flow cytometry procedures were performed to establish the nature of the particulate matter. In addition, leukoreduction filters and blood transfusion sets were used on RBCs units with WPM. RESULTS: The particles were mostly composed of PLTs and WBCs, and fragments of these cells. All macroscopic WPM was removed from RBCs with leukoeduction and transfusion filters. CONCLUSIONS: WPM originated from PLTs and WBCs. Foreign matter (e.g., plastic) was not observed in any of the units. Leukoreduction and transfusion filters can be used to remove macroscopic WPM.     

Description and investigation of white particulate matter in additive solution-1 red blood cell units

BACKGROUND: In January 2003, "white particulate matter" (WPM) was transiently observed in red blood cell (RBC) units collected predominately in the southeastern US. In this report, these events, their chronology, pertinent observations and investigations, and summaries and conclusions associated with WPM during the 2-week observation period are described. CHRONOLOGY AND INVESTIGATIONS: On January 27, 2003, WPM was first identified in RBCs; by January 31, 2003, 110 RBC units containing WPM had been identified. Elective surgeries were postponed. Approximately 400 RBC units containing WPM were inspected in the blood center and characterized into four types: I, II, III, and IV. A variety of preparations of aspirated WPM were made, including light and electron microscopic sections. RESULTS AND CONCLUSIONS: The rate of WPM-containing units was 1.67 percent (1 in 60 units), whereas the background incidence was less than 0.25 percent. Investigations revealed that WPM was composed of activated and nonactivated platelets (PLTs); no toxins, infectious agents, or agents of bioterrorism were identified. WPM correlated with certain variables studied, including PLT-rich components that had been centrifuged with a "hard spin" before leukoreduction and manufactured in one vendor's collection sets. Because the increased rate of appearance of WPM was a transient phenomenon, it is not clear whether this is a newly noticed or a new and different phenomenon from "aggregates" observed in the past.     

Factors affecting the formation of white particulate matter in red blood cell components

BACKGROUND: Recently white particulate matter (WPM) in red blood cell (RBC) components has received increased attention. The nature and causes of WPM formation were investigated. STUDY DESIGN AND METHODS: Whole-blood units were collected from 18 healthy subjects with three different types of collection sets. Six units were collected into each type. Units were divided into four equal parts and stored for 4 hours: two parts at room temperature and two at 4 degrees C. RBCs were prepared from each quarter-unit: two by heavy centrifugation (5000 x g) and two by light centrifugation (2000 x g). Whole blood was inspected for WPM over 4 hours and RBCs over 1 hour. RESULTS: No WPM was detected in whole blood, but WPM was detected in at least one RBC component from 9 of the 18 donations. The 36 components prepared by heavy centrifugation were more likely to contain WPM than the 36 prepared by light centrifugation (50% vs. 19%; p < 0.02). The incidence of WPM was similar among RBCs stored at room temperature and 4 degrees C. Donors of RBCs with WPM had higher total cholesterol levels than donors of components without WPM (191 +/- 20 mg/dL vs. 163 +/- 32 mg/dL; p < 0.04), but there was no difference in triglyceride levels between the two groups. CONCLUSIONS: WPM is an expected consequence of standard RBC manufacturing methods, but it is more frequent in RBCs prepared by heavy centrifugation and from donors with higher cholesterol levels.     

Rapid evaluation of risk of white particulate matter in blood components by a statewide survey of transfusion reactions

BACKGROUND: In January 2003, white particulate matter (WPM) was detected in blood components. Because the composition and cause of WPM was not understood at that time, there was uncertainty about whether WPM could endanger patient safety. To investigate possible adverse patient events associated with WPM, transfusion reaction rates were examined. STUDY DESIGN AND METHODS: A questionnaire was distributed to Georgia medical centers. Data collected included the number of components transfused and reported adverse reactions by component type from January 2002 through January 2003, and date, reaction type, and blood supplier for events in January 2003. RESULTS: Of 124 transfusion services contacted, 108 (87%) responded. During the survey period, there were 1213 reported transfusion reactions and 528,412 units transfused, or 2.3 reactions per 1000 units transfused; for RBCs, 2.4 (range, 1.8-3.1); plasma, 1.5 (range, 0.6-3.5); and PLTs, 3.4 (2.1-5.4) per 1000 units. Transfusion reaction rates by component for January 2003 did not differ significantly from the rate for January 2002 or for the calendar year. The 86 reported reactions that occurred in January 2003 were attributed to bacterial contamination (n = 2, 2.3%), other febrile nonhemolytic (n = 49, 57.0%), allergic (n = 14, 16.3%), and "other" reactions (n = 21, 24.4%); the proportions of reaction types did not differ significantly during the month. CONCLUSION: No overall changes in reported adverse reaction rates occurred over the survey period or in the proportion of reaction types during January 2003 when WPM was detected. Statewide surveillance of transfusion reactions could be useful to evaluate potential threats to blood safety.     

Induction of platelet white blood cell (WBC) aggregate formation by platelets and WBCs in red blood cell units

BACKGROUND: Transfusion of red blood cell (RBC) preparations is independently associated with adverse clinical outcomes in patients with acute cardiovascular disease. This study was designed to define mechanisms potentially contributing. STUDY DESIGN AND METHODS: The presence of platelets (PLTs), activated PLTs (PLTs expressing P-selectin), PLT-monocyte aggregates (PMAs), and PLT-neutrophil aggregates (PNAs) was determined in vitro with the use of flow cytometry in whole blood from healthy volunteers, in RBCs, and in whole blood after adding aliquots of RBCs. Both prestorage leukoreduced and nonleukoreduced RBCs were analyzed. Nonleukoreduced RBCs were subfractionated with the use of centrifugation and filtration to obtain a RBC-free and a cell-free fraction. Formation of PMAs and PNAs was determined in whole blood after the addition of aliquots of these subfractions. RESULTS: Nonleukoreduced RBCs contained 50 +/- 18 percent of the PLTs found in whole blood from healthy volunteers, and 43 +/- 16 percent of the PLTs were activated. Leukoreduced RBCs contained few PLTs (0.2 +/- 0.1% of volunteer blood). The majority (>60%) of white blood cells (WBCs) in nonleukoreduced RBCs were associated with PLTs. The formation of PMAs and PNAs in whole blood was increased approximately fivefold after addition of nonleukoreduced-RBCs (p < 0.0001) and by less than twofold with leukoreduced RBCs (p = 0.01). Addition of the essentially cell-free fraction of nonleukoreduced RBCs did not increase the formation of PNA or PMA in whole blood significantly. CONCLUSION: RBC preparations, particularly nonleukoreduced RBCs, contain activated PLTs and PLT-WBC aggregates and induce formation of PLT-WBC aggregates. This may be one mechanism contributing to adverse outcomes linked to transfusions in patients with cardiovascular disease.     

Transfusion reactions: a comparative observational study of blood components produced before and after implementation of semiautomated production from whole blood

BACKGROUND: A semiautomated method of component production from whole blood was implemented at Canadian Blood Services. To assess safety of the new components, the frequency of adverse transfusion events (ATEs) to platelet components (PCs) and red blood cell (RBCs) produced before and after implementation of the new method was surveyed and compared. STUDY DESIGN AND METHODS: This retrospective, observational, noninferiority study was conducted in 12 sentinel hospitals across Canada. The control group received RBCs in additive solution‐3 (AS‐3) and platelet‐rich plasma (PRP)‐produced platelets (PLTs) for 3 to 11 months before implementation of semiautomated production, and the study group received RBCs in saline‐adenine‐glucose‐mannitol (SAGM) and buffy coat (BC)‐produced PLTs for 3 to 11 months after implementation. ATE definitions at each hospital and standard practice for reporting did not change between control and study periods. Data for analysis were obtained from databases and original report forms. RESULTS: The pooled risk ratio of a reaction to SAGM versus AS‐3 RBCs was 0.77 (95% confidence interval [CI], 0.66‐0.90), suggesting that SAGM products had significantly lower reaction rates than AS‐3 products (p < 0.01). Reported allergic reactions to RBCs decreased from 0.07% (AS‐3) to 0.04% (SAGM). For PLTs, the difference in reaction rates between BC and PRP was not significant (p = 0.37), and the pooled risk ratio of BC versus PRP was 1.14 (95% CI, 0.86‐1.50). CONCLUSION: The change in manufacturing method was associated with lower reaction rates to SAGM RBCs than to AS‐3 RBCs. Pooled BC PLTs were noninferior to random‐donor PRP PLTs with respect to ATEs.     

Supernates from stored red blood cells inhibit platelet aggregation

BACKGROUND: Previously, we reported that red blood cells (RBCs) stored in AS‐5 accumulated proinflammatory substances during storage. We observed in those studies that supernates from nonleukoreduced (NLR) RBCs reduced mean anti‐CD41a‐fluorescein isothiocyanate (FITC) fluorescence on platelets (PLTs), indicative of decreased expression of glycoprotein (GP)IIb/IIIa on the PLT membrane. The objective of this study was to determine if supernates from stored RBCs impaired PLT aggregation as a consequence of reduction in GPIIb/IIIa expression. STUDY DESIGN AND METHODS: Leukoreduced (LR) and NLR RBC units were prepared in AS‐5 and stored at 1 to 6°C for 6 weeks. Supernates from RBC samples collected every 2 weeks were mixed with freshly collected type‐matched blood and incubated for 30 minutes at 37°C. PLTs in each incubated blood sample were evaluated for GPIIb/IIIa expression by flow cytometry and for aggregation response to collagen by whole blood aggregometry. RESULTS: Supernates from stored NLR RBCs reduced CD41a‐FITC fluorescence on PLTs by 15% to 31%. A reduction in fluorescence was induced by supernates of RBCs stored for 14 days and increased as storage time increased. Supernates from Day 42 NLR RBCs reduced the mean amplitude of PLT aggregation by 31% compared to Day 0 supernates and lengthened the time before onset of aggregation by 21%. In addition, amplitude correlated directly and lag time correlated inversely with CD41a‐FITC fluorescence in all samples. Supernates from prestorage LR RBCs did not affect PLT CD41a‐FITC fluorescence or aggregation response. CONCLUSIONS: Substances that decrease expression of GPIIb/IIIa and inhibit PLT aggregation accumulate in NLR RBCs. Accumulation of this material is prevented by leukoreduction.     

In vitro and in vivo evaluation of a whole blood platelet‐sparing leukoreduction filtration system

BACKGROUND: In‐line leukoreduction (LR) filters decrease adverse clinical sequelae caused by residual white blood cells (WBCs). Such filtration, however, can remove platelets (PLTs) needed for production of PLT concentrates (PCs). This study measured in vitro and in vivo efficacy of a new whole blood PLT‐sparing LR filter (WBPSF) system that performs whole blood (WB) LR using a single closed‐system filtration step. The WBPSF provides three final LR products: AS‐5 red blood cells (RBCs), citrate‐phosphate‐dextrose (CPD) PLTs, and CPD plasma. STUDY DESIGN AND METHODS: Volunteers (n = 59) donated WB processed using the WBPSF system. WB filtration time was recorded, and LR WB was processed into AS‐5 LR RBCs, CPD LR PLTs, and LR plasma. Final components were assayed for in vitro indices, and in vivo characteristics for LR AS‐5 RBCs and CPD PLTs were assayed after radiolabeling. RESULTS: WB filtration time averaged 37 minutes. Transfusion products obtained after WBPSF met all in vitro and in vivo Food and Drug Administration (FDA) requirements. Radiolabeling of LR AS‐5 RBCs after WBPSF showed a 24‐hour RBC recovery of 81.3 ± 5.3% after 42 days of storage. In vivo dual ¹¹¹In/⁵¹Cr radiolabeling of PCs manufactured using WBPSF showed a Day 5 recovery ratio of 80 ± 19% versus fresh autologous PLTs and a survival ratio of 81 ± 17% that of fresh autologous PLTs. CONCLUSION: All WBPSF‐derived transfusion products met or exceeded in vitro and in vivo FDA guidelines. This filtration system is suitable for routine blood center or hospital use in the production of LR AS‐5 RBCs, CPD PLTs, and CPD plasma.     

Photochemical inactivation with amotosalen and long-wavelength ultraviolet light of Plasmodium and Babesia in platelet and plasma components

BACKGROUND: Transfusion-transmitted cases of malaria and babesiosis have been well documented. Current efforts to screen out contaminated blood products result in component wastage due to the lack of specific detection methods while donor deferral does not always guarantee safe blood products. This study evaluated the efficacy of a photochemical treatment (PCT) method with amotosalen and long-wavelength ultraviolet light (UVA) to inactivate these agents in red blood cells (RBCs) contaminating platelet (PLT) and plasma components. STUDY DESIGN AND METHODS: Plasmodium falciparum- and Babesia microti-contaminated RBCs seeded into PLT and plasma components were treated with 150 micromol per L amotosalen and 3 J per cm2 UVA. The viability of both pathogens before and after treatment was measured with infectivity assays. Treatment with 150 micromol per L amotosalen and 1 J per cm2 UVA was used to assess the robustness of the PCT system. RESULTS: No viable B. microti was detected in PLTs or plasma after treatment with 150 mol per L amotosalen and 3 J per cm2 UVA, demonstrating a mean inactivation of greater than 5.3 log in PLTs and greater than 5.3 log in plasma. After the same treatment, viable P. falciparum was either absent or below the limit of quantification in three of four replicate experiments both in PLTs and in plasma demonstrating a mean inactivation of at least 6.0 log in PLTs and at least 6.9 log in plasma. Reducing UVA dose to 1 J per cm2 did not significantly affect the level of inactivation. CONCLUSION: P. falciparum and B. microti were highly sensitive to inactivation by PCT. Pathogen inactivation approaches could reduce the risk of transfusion-transmitted parasitic infections and avoid unnecessary donor exclusions.     

Intraoperatively salvaged red blood cells contain nearly no functionally active platelets,but exhibit formation of microparticles: results of a pilot study in orthopedic patients

BACKGROUND: Previous data show improved clot formation after retransfusion of salvaged red blood cells (RBCs). This study was conducted to explore whether such RBCs contain clinically relevant numbers of active residual platelets (PLTs) or exhibit formation of microparticles (MPs). STUDY DESIGN AND METHODS: Thirteen patients undergoing major orthopedic surgery were included in the study, and arterial blood samples from patients and samples from the retransfusion bag were analyzed with various PLT function tests and flow cytometry. RESULTS: With commercial blood cell counters, the numbers of PLTs in the RBC unit were reduced to approximately 25% compared to patients' blood. In contrast, results from flow cytometry showed an 11‐ to 945‐fold reduction in median counts referring to total PLTs and free PLTs. Interestingly, smaller quantities of PLT‐derived MPs were found in samples from the retransfusion bag than in patients' arterial blood. Conversely, RBC‐ and white blood cell–derived MP counts were increased in the retransfusion bag compared to the patient. Rotational thrombelastometry and the Impact‐R system (DiaMed) showed a pronounced impairment of PLT ability with regard to adhesion, aggregation, and clot formation. With the use of confocal microscopy, only a few free thrombocytes were detectable among the huge numbers of RBCs. CONCLUSION: Only few free and thus active PLTs are detectable in processed RBCs. It seems very unlikely that these few PLTs can improve clot strength. Nevertheless, the impact of the detected MPs on thrombin generation needs to be clarified in further studies.     

A flow cytometric method for detection and enumeration of low-level, residual red blood cells in platelets and mononuclear cell products

BACKGROUND: Conventional automated cell counters cannot accurately count residual red blood cells (rRBCs) that are often present in various blood products. A two-color flow cytometric method (FC) was validated for detecting and enumerating rRBCs in platelets (PLTs) and mononuclear cell (MNC) products. STUDY DESIGN AND METHODS: PLT and MNC products for PLTs (CD61-fluorescein isothiocyanate) and rRBC (anti-glycophorin A-phycoerythrin) were double stained, and data were acquired with a flow cytometer. Assay linearity, accuracy, and precision were assessed with a standard-dilution series of rRBCs. This assay was used to determine the rRBCs of apheresis PLTs collected with Trima Accel (Gambro BCT) and MNC products collected with the COBE Spectra (Gambro BCT). RESULTS: The linear range of this assay in PLT and MNC products is 10 to 2000 RBCs per microL (R2=0.994). FC had a mean intraassay coefficient of variation of 11.8 percent at 34 RBCs per microL. A standard clinical hematology analyzer overestimated rRBCs in MNC products by 1.59x10(5)+/-0.7x10(5) RBCs per microL. Apheresis PLTs had a median of 17.4 RBCs per microL, with 99.0 percent containing fewer than 90.0 RBCs per microL. CONCLUSIONS: This method for determining rRBCs in blood products is accurate and repeatable with a lower limit of detection adequate to assess currently available blood products. FC should be considered for determining rRBCs in MNC products.     

Platelet counting in platelet concentrates with various automated hematology analyzers

BACKGROUND: Hematology analyzers use impedance, optical, and/or immunologic techniques for counting platelets (PLTs). PLT counting in whole blood has been validated thoroughly; however, this is not the case for PLT counting in PLT concentrates (PCs), in which red cells (RBCs) are absent. Therefore, this study is focused on PLT counting in PCs to study use of ethylenediaminetetraacetate (EDTA), carryover, and accuracy of the analyzers. STUDY DESIGN AND METHODS: In total six hematology analyzers (AcT 8, Beckman Coulter; ADVIA 2,120, Bayer; Cell-Dyn 4,000, Abbott; Onyx, Beckman Coulter; K4,500, Sysmex; and XT 2,000i, Sysmex) were tested for PLT counting. PC samples with various PLT concentrations were made (0-1,700 x 10(9)/L) and measured 10 times. Carryover was determined five times. RESULTS: PC samples (1,000 x 10(9) PLTs/L) in EDTA tubes showed significantly higher PLT counts than samples in "dry" tubes for all analyzers except for the Cell-Dyn 4,000 with the impedance technique. Carryover was not more than 0.3 percent for all analyzers. The K4,500 showed the most accurate results, whereas the Cell-Dyn 4,000 with the impedance technique had low accuracy due to an overestimation of more than 20 percent. CONCLUSION: Most tested analyzers seemed to be suitable for counting PLTs in PCs. All hematology analyzers should be validated for counting PLTs in absence of RBCs as is the case in PCs, in addition to validation of PLT counting in whole blood.     

Outpatient transfusions and occurrence of serious noninfectious transfusion-related complications among US elderly, 2007-2008: utility of large administrative databases in blood safety research

BACKGROUND: Transfusion‐related acute lung injury (TRALI) and hemolytic transfusion reactions account for significant transfusion‐related morbidity and mortality in the United States. Our study evaluated types and quantities of transfused components as well as occurrence of TRALI, ABO, and Rh incompatibilities among the US elderly in the institutional outpatient setting during 2007 to 2008. STUDY DESIGN AND METHODS: This retrospective claims‐based study utilized the Centers for Medicare & Medicaid Services' large administrative databases. Transfusions were identified by recorded procedure and revenue center codes, while complications were ascertained via ICD‐9‐CM diagnosis codes. The study quantified blood use based on revenue center units. RESULTS: Among 26,054,242 and 25,662,864 Medicare elderly in 2007 and 2008, a total of 241,055 (0.9%) and 251,284 (1.0%) had outpatient transfusions. Leukoreduced red blood cells (LR‐RBCs) was the most frequently transfused single blood component (60.1 and 61.3%, respectively) each year. Likewise, LR‐RBCs and LR pheresis platelets (LR‐PLTs) was the most frequent component combination (2.4 and 2.6%, respectively). TRALI rate comparison for RBCs and PLTs versus RBCs only showed higher rate for RBCs and PLTs (p = 0.033). In 2007 and 2008, ABO incompatibility rate comparison for irradiated (IR) LR‐RBCs versus LR‐RBCs showed higher rates for IR LR‐RBCs (rate ratio [RR] 37.4, 95% confidence interval [CI] 10.6‐132.6; and RR 31.3, 95% CI 11.6‐84.4, respectively). CONCLUSION: This study shows potential usefulness of Medicare databases in assessment of blood utilization, transfusion‐related complications, and risk factors among US elderly in the outpatient setting. It suggests limitations (e.g., need for several years of data to better assess rare complications) and importance of databases as hypothesis‐generating tool to supplement blood safety research.     

Preparation of FFP as a by-product of plateletpheresis

BACKGROUND: To reduce the production costs of single-donor platelets (SDPs), a study was conducted to investigate whether plasma collected as a by-product of plateletpheresis satisfies the quality requirements for FFP without impairing the quality of the SDP component. STUDY DESIGN AND METHODS: Ninety-two donors with platelet (PLT) counts <270 x 10(9) per L underwent plateletpheresis using an automated cell separator (Spectra Apheresis System with the Leukoreduction System [LRS], Gambro BCT, Lakewood, CO). The machine was programmed to collect 3 x 10(11) PLTs in 250 mL of plasma with an additional unit of 350 mL of plasma or 3 x 10(11) PLTs in 250 mL of plasma without additional plasma in 10 procedures. FV and FVIII and residual RBCs, WBCs, and PLTs in the plasma were measured for quality control. RESULTS: FV was 0.87 +/- 0.18 IU per mL, and FVIII was 1.32 +/- 0.48 IU per mL in the plasma components (n = 41). The recovery was 94.1 +/- 5.5 percent for FV and 102.2 +/- 9.5 percent for FVIII when compared with the donors' predonation values. Residual cells were 0.002 +/- 0.009 x 10(9) RBCs per L (n = 30), 12 +/- 6 x 10(9) PLTs per L (n = 30), and 0.32 +/- 0.37 x 10(6) WBCs per L (n = 92). CONCLUSIONS: Using the automated cell separator and special software, it is possible to collect plasma as a by-product of plateletpheresis that meets the properties requested for FFP without impairing the quality of the SDP components. The content of clotting factors is within the requested range for FFP. Residual cell counts are within all European and U.S. specifications for FFP, and the WBC content even satisfies the criteria for WBC-reduced blood components. The collection of FFP as a by-product does not cause any additional costs and thus helps to reduce the costs in preparing blood components.     

Emergency department blood transfusion predicts early massive transfusion and early blood component requirement

BACKGROUND: The purpose of this study was to evaluate the ability of uncrossmatched transfusions in the emergency department (ED) to predict early (<6 hr) massive transfusion (MT) of red blood cells (RBCs) and blood components. STUDY DESIGN AND METHODS: All patients admitted to a Level 1 trauma center between July 2005 and June 2007 who received any transfusions and were transported directly from the scene of injury were included. Early MT was defined as the need for 10 U or more or RBCs in the first 6 hours. Early MT plasma was defined as 6 U or more of plasma in the first 6 hours. Early MT platelets (PLTs) were defined as two or more apheresis transfusions in the first 6 hours. Univariate and multivariate analyses were performed. RESULTS: A total of 485 patients (34%) received ED transfusions (ED RBC+) and 956 (66%) did not receive ED transfusions (ED RBC–). ED RBC+ patients were younger, were more likely to be male, and arrived with more severe injuries. Multivariate regression identified ED transfusion of uncrossmatched RBC as an independent predictor of requiring early MT of RBCs (odds ratio [OR], 3.5; 95% confidence interval [CI], 1.36‐7.59; p = 0.001), plasma (OR, 2.7; 95% CI, 1.66‐4.39; p < 0.001), and PLTs (OR, 1.9; 95% CI, 1.08‐3.41; p = 0.025). CONCLUSION: Patients receiving uncrossmatched RBCs in the ED are more than three times more likely to receive early MT of RBCs. Additionally, patients transfused with ED RBCs are more likely to receive 6 units or more of plasma and two or more apheresis PLT transfusions. Given these findings, ED transfusion of uncrossmatched RBCs should be considered a potential trigger for activation of an institution's MT protocol.     

Effect on the quality of blood components after simulated blood transfusions using volumetric infusion pumps

BACKGROUND: It is unknown whether the use of volumetric infusion pumps for the transfusion of red blood cells (RBCs) or platelet (PLT) concentrates (PCs) affects the quality of the blood components. We therefore investigated the in vitro quality of these components after use of infusion pumps. STUDY DESIGN AND METHODS: Ten different volumetric infusion pumps were used to simulate transfusion with RBCs and PCs. To prevent donor‐dependent differences multiple units were pooled and divided into equal portions. The storage time of RBCs was 30 to 35 days (n = 10 experiments), and for PCs, either 2 (n = 5) or 7 days (n = 5). For RBCs an infusion rate of 100 or 300 mL/hr was used, and for PCs, 600 mL/hr. Transfusions without an infusion pump served as a reference. RESULTS: None of the infusion pumps induced an increase of free hemoglobin, annexin A5 binding, or formation of echinocytes in RBCs compared to reference units. In 2‐ and 7‐day‐old PCs no effect was shown on PLT concentration, annexin A5 binding, mean PLT volume, and morphology score compared to the reference. The CD62P expression of 2‐day‐old PCs was significantly lower after transfusion compared to the reference, that is, 11.7 ± 2.1% versus 8.1 ± 1.3% (p < 0.01). CONCLUSION: There was no adverse effect on the in vitro quality of RBCs or PCs after simulated transfusion using volumetric infusion pumps. A decrease in PLT activation was observed, which can probably be explained by capturing of activated or damaged PLTs in the 200‐µm filter present in the infusion system.     

Multicenter evaluation of a whole-blood filter that saves platelets

BACKGROUND: Whole-blood (WB) leukoreduction filters in current use retain the majority of PLTs. A new whole-blood filter, which retains significantly fewer of the PLTs (or saves PLTs [WB-SP]), has been developed. The performance characteristics of the WB-SP filter have been evaluated in a multicenter study. STUDY DESIGN AND METHODS: A total of 617 units of WB was collected into quadruple bag sets with an integrated WB-SP filter, leukoreduced, and processed into leukoreduced RBCs (LR-RBC), plasma (LR-PL), and buffy coats (LR-BC) from which, pooled, leukoreduced, PLT concentrates (LR-PCs) were produced. Recovery, yield, and residual WBCs were assessed in prepared blood components. RESULTS: The median residual WBC number in the LR-RBCs was 0.05 x 10(6) (range, <0.05-3.8), exceeding 1 x 10(6) in 0.6 percent of the units. Median Hb content in LR-RBC was 50 g (range, 34-72), reflecting a final RBC recovery of 81 +/- 6 percent. The median WBC content of the LR-PC was 0.05 x 10(6) (range, <0.05-0.28), with none exceeding 1 x 10(6). The median PLT content of the LR-PC, per individual donation, was 6.4 x 10(10) (range, 4.1-10.7), representing a final recovery of 62 +/- 10 percent. The mean FVIII activity was 104 +/- 25 percent and 83 +/- 11 percent in plasma separated from fresh or overnight stored WB, respectively. CONCLUSION: Use of the WB-SP filter makes it possible to obtain three leukoreduced blood components with only one filtration step. The WB-SP filter showed good leukoreduction performance and recovery of all blood components including PLTs.     

The effect of whole-blood storage time on the number of white cells and platelets in whole blood and in white cell-reduced red cells

BACKGROUND: Whole blood (WB) can be stored for some time before it is processed into components. After introduction of universal white cell (WBC) reduction, it was observed that longer WB storage was associated with more residual WBCs in the WBC-reduced red cells (RBCs). Also, weak propidium iodide (PI)-positive events were observed in the flow cytometric WBC counting method, presumably WBC fragments. The effect of storage time on the composition of WB and subsequently prepared WBC-reduced RBCs was studied. STUDY DESIGN AND METHODS: WB was collected in bottom-and-top collection systems with inline filters, obtained from Baxter, Fresenius, or MacoPharma. Units were stored at room temperature and separated into components in 4-hour intervals between 4 and 24 hours after collection. RBCs were WBC-reduced by inline filtration (approx. 50/group). RESULTS: Platelet (PLT) counts were lower in WB stored for 4 to 8 hours compared to 20 to 24 hours (mean +/- SD): 79 +/- 31 versus 102 +/- 30 for Baxter (p < 0.01); 91 +/- 31 versus 101 +/- 35 for Fresenius (not significant); and 73 +/- 47 versus 97 +/- 31 (all x 10(9) per unit) for MacoPharma (p < 0.01), respectively. The median residual WBC counts in WBC-reduced RBCs for WB stored for 4 to 8 and 20 to 24 hours were 0.03 versus 0.17 for Baxter (p < 0.001), 0.00 versus 0.06 for Fresenius (p < 0.001), and 0.13 versus 0.26 (all x 10(6) per unit) for MacoPharma (not significant), respectively. All WBC-reduced RBCs contained fewer than 5 x 10(6) WBCs per unit. A longer storage time of WB was associated with more weak PI-positive events, irrespective of the filter. CONCLUSION: Longer storage of WB before processing results in counting higher numbers of PLTs in WB, higher numbers of WBCs in WBC-reduced RBCs, and more weak PI-positive events.     

Trypanosoma cruzi infection in North America and Spain: evidence in support of transfusion transmission (CME)

BACKGROUND: The United States, Canada, and Spain perform selective testing of blood donors for Trypanosoma cruzi infection (Chagas disease) to prevent transfusion transmission. The donor, product, and patient characteristics associated with transfusion‐transmitted infections are reviewed and the infectivity of components from donors with serologic evidence of infection is estimated. STUDY DESIGN AND METHODS: A systematic review of transfusion‐transmitted T. cruzi cases and recipient tracing undertaken in North America and Spain is described. Cases were assessed for the imputability of the evidence for transfusion transmission. RESULTS: T. cruzi infection in 20 transfusion recipients was linked to 18 serologically confirmed donors between 1987 and 2011, including 11 identified only by recipient tracing. Cases were geographically widely distributed and were not associated with incident or autochthonous infections. Index clinical cases were described only in immunocompromised patients. All definite transmissions (n = 11) implicated apheresis or whole blood–derived platelets (PLTs), including leukoreduced and irradiated products. There is no evidence of transmission by red blood cells (RBCs) or frozen products, while transmission by whole blood transfusion remains a possibility. Recipient tracing reveals low component infectivity from serologically confirmed, infected donors of 1.7% (95% confidence interval [CI], 0.7%‐3.5%) overall: 13.3% (95% CI, 5.6%‐25.7%) for PLTs, 0.0% (95% CI, 0.0%‐1.5%) for RBCs, and 0.0% (95% CI, 0%‐3.7%) for plasma and cryoprecipitate. CONCLUSIONS: T. cruzi is transmitted by PLT components from some donors with serologic evidence of infection. Evidence of transmission before the implementation of widespread testing in the countries studied is sparse, and selective testing of only PLT and fresh whole blood donations should be considered.