Red cell transfusion in medicine: Future challenges

Many side-effects of red blood cell transfusion have been described. They include iron-overload, as well as allo- and autoantibody formation against red cells. During storage, erythrocytes undergo complex structural and biochemical changes. It has been suggested that accelerated and/or aberrant forms of the physiological erythrocyte aging process underlie the red cell storage lesion. This storage lesion may contribute to side-effects of transfusion as endothelial damage by release of internal erythrocyte constituents, (pro)inflammatory consequences, hampered microcirculation and oxygen delivery. Understanding the process that determines the fate of red blood cells after transfusion may contribute to the prevention of side-effects after red blood cell transfusion. This should be the focus of research on red blood cell transfusion in clinical transfusion medicine.     

Conséquences sur les PSL de la déleucocytation par filtration du sang total avec le filtre intégré Leucoflex LST1: Évaluation du filtre Leucoflex LST1

The aim of this study is to evaluate the effects of whole blood filtration after a storage time of 20 - 24 hours at laboratory temperature using the in line filter Leucoflex^® LST1.The study concerns 49 blood donations in which we studied leukocyte depletion, proteins (IgG, IgA, IgM, haptoglobin, C3, C4), coagulation factors (fibrinogen, factors XII, XI, IX, VIII, V, proteins S and C, plasminogen, tPA, D-Dimers, PDF) at day 1, the parameters of conservation (ATP, 2–3 DPG, extra cellular potassium, haemolysis, pH) of red blood cell concentrates (RCCs) and bacteriological sterility at day 1 and 42.Despite a correct leukocyte depletion (mean depletion of 3,96 log), a 10 fold higher mean level of residual leukocytes/unit than with buffy coat poor RCC filtration (0,514.10⁶vs 0,051.10⁶) is observed. Moreover a lot of concentrates are not in accordance with French regulations (7/42 with more than 1.10⁶ leukocytes/unit).The variation of the rates of IgG, IgA, IgM, haptoglobin, C4 and protein C is not significant. For the others there is a slight decrease with a mean level remaining in a physiological range. No sign of activation is noted.The sterility assays remain negative and the RCC conservation is not altered.In conclusion, even if the quality of the leukocyte depletion is not satisfactory in our study and has to be stated more precisely by multicenter studies, the whole blood filtration does not alter the quality of the derived components and allows us obtain RCC in a bigger volume and containing more haemoglobin than with the classical procedure after removing the buffy-coat ^[10].     

Analysis of 516 reports of reactions after the transfusion of labile blood products]

BACKGROUND: In order to assess the implemented preventive measures of transfusion reactions (TR) and to make a study of residual reactions, we analyzed 516 TR reports from 14 hospitals, for three years since 1996 to 1998. METHODS: Clinical signs were classified according to seven etiologic categories. Systematic anti-erythrocyte and anti-leucocyte detection, as well as bacterial control of the returned bag were performed. RESULTS: The TR incidence is 3.7 per 1.000 products. Platelet concentrates (PC) provoke 7.4 TR per 1.000 transfusions, and red cell concentrates (RCC) 3.8. There are as many TR with apheresis platelets (AP), pre-storage leuco-depleted, as with random platelets, post-storage leuco-depleted, and as many with leuco-depleted RCC as with non leuco-depleted RCC. Leuco-depleted AP provoke more allergic reactions than other blood components. TR with AP are much more frequent in children than in adults. Plasma removal from AP before transfusion decreases reaction frequency. CONCLUSIONS: The lack in efficacy failure of pre-storage deleucocytation in TR prevention should be due to related patient factors. Etiology of AP allergic reactions deserves further study. PC suspension in synthetic medium before transfusion is an efficient means for RT decreasing. Hemovigilance system has to be improved so that all TR be reported.     

National French observatory of the quality of blood components for transfusion.

PURPOSE: Since 1998, prestorage leucoreduction of cellular blood components (BC) is mandatory in France. The French Blood Service needs to follow the data on the quality of the BC prepared by blood centers. This article gives an overview of the quality control (QC) data from 2001 to 2006. MATERIAL AND METHODS: QC data are submitted to a central data bank by each centre. The data are stratified according to preparation process for analysis of key performance criteria - residual leukocytes and haemoglobin or platelet content. BC preparation processes, methods for measuring haemoglobin and platelet content, and for counting residual leukocytes are those routinely employed by centers. RESULTS: The preparation process of red cell concentrates (RCC) influences the haemoglobin content: 57.6+/-6.8 g per unit versus 50.9+/-5.4 g per unit for whole blood or RCC filtration, respectively. Apheresis RCC exhibits a reduced variability (51.2+/-3.4 g per unit). For apheresis platelet concentrates, the median residual leukocyte count remains low for all separators (0.019-0.044 x 10(6)leukocytes per unit, in 2006). However, the percentage of units exceeding 1 x 10(6)leukocytes per unit is significantly higher with one separator (1.8% versus 0.8%, in 2006). For pooled buffy-coat derived platelets, we observed a significant increase in platelet recovery throughout the years (0.66-0.77 x 10(11)platelets per buffy-coat in 2001 and 2006, respectively). CONCLUSION: Our QC data show an overall compliance with the requirements for cellular BC. Our data bank is useful to inform on the performance of leucoreduced BC preparation processes carried out with market available devices.     

The role and impact of the transfusion medicine consultation service in the management of patients in the hematopoietic transplant service: A retrospective analysis

BackgroundAdverse reactions secondary to transfusion of incorrect blood components can be fatal. We have established numerous processes to prevent these reactions in patients with cancer who continuously need blood component support, especially hematopoietic transplant recipients. The development of an active transfusion medicine consultation service at our institution to serve patients undergoing hematopoietic transplantation has led to more organized and simpler management of providing blood components to such patients.Study design and methodsSafety tools were employed to attain our goal of providing safe blood components to hematopoietic transplant recipients. These tools were consultation request forms, blood component selection stickers on the patients’ charts, and transfusion medicine physician consultation notes posted in the patients’ medical records. One hundred randomly selected hematopoietic transplant recipients were reviewed over 16 months. Fifty patients received blood components from ABO-compatible donors, whereas the other 50 patients received components from ABO-incompatible donors. Deviation reports regarding the issuance of blood components in these patients over the study period were reviewed retrospectively.ResultsWe identified eight reported deviations from the recommended blood components: red blood cells in one case, fresh frozen plasma in one case, single donor platelets in one case, and random donor platelets in five cases. Our transfusion service issued all eight components, but none of them were transfused. In all eight cases, the blood components were intended for transfusion to ABO-mismatched hematopoietic transplant recipients. Nurses identified the incorrect blood components by verifying the recommended blood groups on the patients’ chart stickers, returned the components to the transfusion service, and transfused the correct blood components.ConclusionUse of these safety tools has improved the safety culture regarding transfusion of blood components in hematopoietic transplant recipients at our institution.     

Evidence for indications of fresh frozen plasma

There continues to be a general but unfounded enthusiasm for fresh frozen plasma (FFP) usage across a range of clinical specialties in hospital practice. Clinical use of plasma has grown steadily over the last two decades in many countries. In England and Wales, there has not been a significant reduction in the use of FFP over the last few years, unlike red cells. There is also evidence of variation in usage among countries--use in England and Wales may be proportionately less per patient than current levels of usage in other European countries and the United States. Plasma for transfusion is most often used where there is abnormal coagulation screening tests, either therapeutically in the face of bleeding, or prophylactically in non-bleeding subjects prior to invasive procedures or surgery. Little evidence exists to inform best therapeutic plasma transfusion practice. Most studies have described plasma use in a prophylactic setting, in which laboratory abnormalities of coagulation tests are considered a predictive risk factor for bleeding prior to invasive procedures. The strongest randomised controlled trial (RCT) evidence indicates that prophylactic plasma for transfusion is not effective across a range of different clinical settings and this is supported by data from non-randomised studies in patients with mild to moderate abnormalities in coagulation tests. There are also uncertainties whether plasma consistently improves the laboratory results for patients with mild to moderate abnormalities in coagulation tests. There is a need to undertake new trials evaluating the efficacy and adverse effects of plasma, both in bleeding and non-bleeding patients, to understand whether the "presumed" benefits outweigh the "real risks". In addition, new haemostatic tests should be validated which better define risk of bleeding.     

去白细胞采输血器的血液相容性体外评价

去白细胞采输血器是用于过滤全血或红细胞悬液中白细胞的医疗器械类产品,为保证其临床应用的安全性,本文对去白细胞采输血器（型号：NGL/RF-XZ-200）进行血液相容性体外评价.选择去白细胞采输血器的3个主要部件：软管、塑料血袋和去白细胞滤器滤膜为试验样品,以进口同类产品作为参照,按照GB/T 16886.4-2003和GB/T 14233.2-2005标准的要求和方法,进行溶血、PTT以及体外自发性血小板聚集3个体外血液相容性指标测试.结果 显示试验样品溶血率小于5%,样品凝血时间和血小板最大聚集率与参照样品无显著性差异（P〉0.05）.该结果表明去白细胞采输血器对血液成分和功能无明显不良影响,具有良好的血液相容性.     

Étude pilote des caractéristiques des patients transfusés et des produits sanguins labiles utilisés

The aim of this study was to describe blood recipients and blood components transfused during the first 24 hours in 13 French hospitals. We included all blood recipients who had not had any blood transfusion within the past six months. Recipients were screened for red cell alloantibodies, the alanine aminotransferase activity and specific viral markers (hepatitis B and C, Human Immunodeficiency Virus). Eligible patients represented 47% of the all transfused. Among the 371 patients included, 57% were males and 71% were transfused in a surgical unit. Alloantibodies, non specific and specific viral markers were detected in 3%, 19% and 2% respectively. Among the patients included, 42 received 172 autologous units. In total, 1056 allogeneic units (an average of 3 units per patient) were transfused; blood products were leucocyte-depleted (49%) or leucocyte-poor (20%) ; 54% of red cell units were matched for antigens Rh and Kell. Neoplasms were the most frequently reported disease for which patients were transfused. This study provides baseline blood transfusion information on recipients and blood utilization for a specific period in French hospitals. Following this study, a national study will allow the clarification of the characteristics, for instance the surgical procedures requiring transfusion.     

Mouse models of sickle cell disease

In the absence of a natural animal model for sickle cell disease, transgenic mouse models have been generated to better understand the complex pathophysiology of the disease and to evaluate potential specific therapies. In the early nineties, the simple addition of human globin genes induced the expression of hemoglobin S (HbS) or HbS-related human hemoglobins in mice still expressing mouse hemoglobin. To increase the proportion of human hemoglobin and the severity of the mouse sickle cell syndrome, the proportion of mouse hemoglobin could be decreased by a combination of mouse alpha- and beta-thalassemic defects, leading to complex genotypes and mild disease. Following the discovery of gene targeting in the mouse embryonic stem cells (ES cells), it was made possible to knock out all mouse adult globin genes (2alpha and 2beta) and to add the human homologous genes elsewhere in the mouse genome. In addition, the human gamma gene of fetal hemoglobin was protecting the fetus from HbS polymer formation. Accordingly, the resulting adult mouse models obtained in 1997, expressing human HbS-only, had a very severe anemia (Hb=5-6 g/dL). In order to survive, these "HbS-only mice" had to reduce the HbS concentration within the red blood cells. The phenotype could be less severe by adding modified human gamma genes, still expressed in adult mice. In 2006, a last "S-only" model was obtained by homologous knock in, replacing the mouse globin genes by human genes. This array of models contributes to better understand the role of different interacting factors in the complexity of sickle cell events, such as red cell defects, changes in blood flow and vaso-occlusion, hyperhemolysis, vascular tone dysregulation, oxidations, inflammation, activation and adhesion of cells, ischemia, reperfusion... In addition, each model has an appropriate usefulness to evaluate experimental therapies in vivo and to perform preclinical studies.     

Leukocyte Filtration Mechanisms. Factors Influencing the Removal of Infectious Agents From red Cell Concentrates

The purpose of the present overview was to determine the factors influencing the removal of infectious agents from red cell concentrates by filtration. In general, the efficacy of the filtration method depends on the physical as well as the functional properties of blood cells. These properties are highly influenced by the changes exerted on the blood cells during blood collection, processing and storage and the filtration method itself. In particular, the removal of infectious agents of red cell concentrates by filtration will be determined by the type of virus and therewith the binding towards leukocytes, the type of bacteria and holding period before filtration, the deformability of infected cells and the disintegration of cells in the filter     

Transfusion de concentrés de globules rouges à Yaoundé, Cameroun : quelle qualité ?

As part of a quality assurance process in the transfusion service of a hospital blood bank of Yaoundé, Cameroon, a selection of units of red cell concentrates (RCC) were evaluated for volume, haemoglobin, and haematocrit levels as well as blood cell content. Blood samples were all collected into standard double blood bags containing an anticoagulant, citrate-phosphate-dextrose and adenine. During a three-month period, 35 bags intended for the preparation of the RCC were analysed. After relevant screening for transfusion transmissible infections ,and ABO and rhesus (RH1) blood grouping, the bags were centrifuged to obtain RCC. The resultant red cell bags were weighed and the volumes estimated. Full blood counts were performed on samples of the RCC using an electronic particle counter (DIANA 5, HYCEL Diagnostics, Reims, France). The results obtained showed that, based on ISO 9001: 2000 norms, there were 57, 66 and 80% of RCC respectively with volumes, hemoglobin levels as well as hematocrit that were in conformity with the norms. When the data was analysed based on the Algerian norms, 83, 66 and 95% respectively conformed. The significance of these findings and the need for establishing local norms for quality assurance in our community are discussed.     

Étude rhéo-acoustique de la rupture d''agrégates de particules en suspension dans un champ de cisaillement Application à la désagrégation des globules rouges

Rheo-acoustic study of particle aggregate break-up in a shear flow. Application to red blood cell aggregates.Shear-induced disruption of reversible flocs in a concentrated suspension is investigated by ultrasound backscattering in the low shear regime. Fractal flocs are considered as non-Brownian scatterers much smaller than the wavelength, with acoustic properties close to those of the surrounding medium, so that the attenuation of the coherent field is weak and multiple scattering can be neglected. The concept of variance in local particle volume fraction is used to deduce a first order expression of the ultrasound scattering coefficient (cross-section per unit volume) for Rayleigh scatterers in a dense suspension. On the basis of a scaling law for the shear-induced disruption of aggregates, the shear stress dependence of the ultrasonic scattered intensity from a dense suspension of flocs is derived. In a second part, the shear break-up of hardened red blood cell aggregates is investigated in a plane—plane flow geometry by ultrasound scattering. Rheo-acoustical experiments are analysed within the framework of the self consistent field approximation and the scaling laws currently used in microrheological models. Finally, the ability of ultrasonic, light reflectometry and viscometry methods to provide quantitative information about red blood cell aggregation and membrane adhesiveness is discussed.     

Use of whole blood as the routine transfusion product in Africa

In many countries in sub‐Saharan Africa (sSA) whole blood is more commonly available from blood transfusion services than red cell concentrates. Although in recent years, many countries have made significant progress in the implementing component preparation, this has largely been facilitated by external funding support. The large majority of rather than none of the sSA countries are leucocyte‐reducing or irradiating blood for transfusion. Systems for the routine detection of adverse consequences of blood transfusions (haemovigilance) only exist where transfusion safety has been identified as a health priority by the government. As a resource, the availability of blood transfusion in these countries is limited since less than 5 units of blood were donated per 1000 population far below the recommended requirement of 20 units/1000 per year. Young children are the main users of blood for transfusion in these sSA regions, largely due severe anaemia secondary to infection and sickle cell anaemia. Outcomes for children with severe anaemia are poor, even in those receiving a transfusion. Although it has been speculated that this may be due to transfusion‐related cardiac or pulmonary events, available data from observational studies and clinical trials indicate that these are rare complications of transfusion. Evidence from clinical physiology studies including those examining myocardial functions before and after the receipt of whole blood provide reassuring evidence that volume overload is rare and clinical trials reporting outcomes in children receiving whole blood transfusion, including a Phase II trial examining higher volumes, indicate that there is no evidence of cardiac or pulmonary overload events.     

Erythroid adhesion molecules in sickle cell disease: Effect of hydroxyurea

In sickle cell disease, the complex scenario of vaso-occlusive crisis (VOC) typical of this disease is clearly multifactorial and not fully understood. Cell-cell and cell-cell matrix interactions mediated by adhesive molecules present on blood cells and endothelial cells (ECs) are thought to play an important role. Early studies have shown that sickle red blood cells (RBCs) are abnormally adherent to ECs and some of the molecules involved in these interactions have been identified, such as the alpha4beta1 integrin and CD36, exclusively present on stress reticulocytes, and CD47 on mature RBCs. More recently, attention focused on Lu/BCAM, the unique RBC receptor for laminin, and on ICAM-4, a red cell-specific adhesion receptor, which is a ligand for a large repertoire of integrins (alphaLbeta2, alphaMbeta2, alphaxbeta2, alphaVbeta3). The counter-receptors on ECs and the role of plasma proteins forming bridges between blood cells and ECs have been clarified in part. It has also been shown that reticulocytes from SCD patients express higher levels of alpha4beta1 integrin and CD36, and that under hydroxyurea (HU) therapy, both cell adhesion to ECs or extracellular matrix proteins and the levels of these adhesion molecules are reduced. These findings are consistent with the view that enhanced adhesion of blood cells to ECs is largely determined by the membrane expression level of adhesion molecules and could be a crucial factor for triggering or aggravating vaso-occlusion. In SCD patients, membrane expression of Lu/BCAM (and perhaps ICAM-4) is enhanced on RBCs whose adherence to laminin or ECs is also increased. Interestingly, Lu/BCAM- and ICAM-4-mediated adhesion are enhanced by the stress mediator epinephrine through a PKA-dependent pathway initiated by a rise in intracellular cAMP and leading to receptor activation by phosphorylation according to the same signaling pathway. More recently, studies based on quantitative expression analysis of adhesion molecules on RBCs and during erythroid differentiation in patients undergoing HU therapy, surprisingly revealed that Lu/BCAM level was enhanced, although alpha4beta1, CD36 and ICAM-4 (to a lower extent) levels were indeed reduced. CD47 and CD147 expression were also enhanced in HU-treated patients. Based on these findings we suggest that the signalization cascade leading to receptor activation rather than the expression level only of adhesion molecules may be the critical factor regulating cell adhesion, although both mechanisms are not mutually exclusive.     

Endothelial signalling by Ig-like cell adhesion molecules

Leukocyte transendothelial migration is controlled by chemokine-induced signalling in leukocytes and integrin-ligand-induced bidirectional signalling in both leukocytes and endothelial cells. It is now generally accepted that endothelial signalling following leukocyte adhesion, serves to facilitate the crossing of the endothelium, be it via the paracellular or transcellular route. This brief overview discusses the main findings within this area and highlights some recent findings that shed new light on adhesion-induced signalling in the context of leukocyte transendothelial migration.     

Quality indicators of blood utilization: three College of American Pathologists Q-Probes studies of 12,288,404 red blood cell units in 1639 hospitals

OBJECTIVES: To determine the normative rates of blood unit crossmatched to transfused (C:T) ratios, red blood cell (RBC) unit wastage, and RBC unit expiration that exist in hospital communities throughout the United States, and to examine hospital blood bank practices associated with more desirable (lower) rates. DESIGN: In 3 separate studies, participants in the College of American Pathologists Q-Probes laboratory quality improvement program collected data retrospectively on the number of transfusion crossmatches performed in their institutions and the number of RBC-containing units that were transfused into patients, the number of units that expired (outdated) prior to being utilized, and the number that were wasted due to mishandling. Participants also completed questionnaires describing their hospitals' and blood banks' laboratory and transfusion practices. SETTING AND PARTICIPANTS: One thousand six hundred thirty-nine public and private institutions, well more than 80% of which were known to be located in the United States. MAIN OUTCOME MEASURES: Quality indicators of blood utilization (namely, the C:T ratio, the rate of RBC unit expiration, and the rate of RBC unit wastage). RESULTS: Participants submitted data on 12,288,404 RBC unit transfusions. The C:T ratios were 1.5 or less in the top-performing 10% of participating institutions (90th percentile and above), 1.8 to 1.9 in the midrange of participating institutions (50th percentile), and 2.4 or greater in the bottom-performing 10% of participating institutions (10th percentile and below). Red blood cell unit expiration rates were 0.1% or less at the 90th percentile and above, 0.3% to 0.9% at the 50th percentile, and 3.5% or greater at the 10th percentile and below. Red blood cell unit wastage rates were 0.1% or less at the 90th percentile and above, 0.1% to 0.4% at the 50th percentile, and 0.7% or greater at the 10th percentile and below. Depending on which quality indicator was examined, lower values (ie, better performances) were found in institutions that had fewer than 200 hospital beds, no teaching programs, no on-site full-time medical directors of transfusion services, did not utilize maximum surgical blood order schedules, set C:T threshold goals of 2.0 or less, monitored categories of health care workers responsible for RBC wastage, monitored requests for RBC components by transfusion indication, did not accept short-dated units from blood distribution centers, and if they did accept short-dated units, were allowed to return those units to the distribution centers. CONCLUSIONS: Hospital blood bank personnel can achieve C:T ratios below 2.0, RBC unit expiration rates below 1.0%, and RBC unit wastage rates below 0.5%. Lower C:T ratios and/or RBC unit expiration rates were associated with blood bank personnel setting C:T thresholds of 2.0 or less, monitoring requests for blood components by transfusion indication criteria, monitoring categories of health care workers responsible for blood wastage, not accepting short-dated units from blood distribution centers, and if short-dated units were accepted, being allowed to return those units to the blood distribution center. These practices were not associated with lower blood wastage rates.     

Use of plasma: Clinical indications and types of plasma components in Sweden

The use of plasma in Sweden is relatively high compared to other countries in the European Union. An analysis of all transfusion recipients in Orebro county during the whole year 2000 was performed. There were 3159 transfusion recipients of whom 96% had a registered diagnosis and 50% had undergone a "true" operation. Seven hundred and eleven patients (23%) had received plasma. Significantly more operated than nonoperated and more men than women received plasma. The typical plasma recipient was a man undergoing cardiovascular surgery. In Sweden there are two main types of plasma components: fresh frozen (FFP) and nonfrozen liquid plasma stored for up to 14 days, both considered to be clinically equal for most indications. The quality of these components as well as stored thawed FFP has been studied. The major storage effect was cold-induced contact activation and thereby consumption of C1 esterase inhibitor (C1INH) by day 14 in 22%. The citrate content in plasma sustained the overall coagulation function over 14 days. Other studies have shown that the levels of FV and ADAMTS 13 after 14 days remain at 70% or more compared to those for FFP. Since it is immediately available, liquid, nonfrozen or thawed, plasma is of great value in emergencies. Quality criteria for plasma components need to be assessed against evidence based indications and published in guidelines.     

Consensus and controversies in platelet transfusion: Trigger for indication, and platelet dose

Platelet transfusion is about to commemorate its 50th year since its introduction in therapeutics. It is then surprising to see, that in spite of reaching this respectful age, we have not been able to definitely establish all the aspects related to its clinical use. Some of these facets are platelet transfusion threshold and the platelet dose to administer. Historically, two different transfusion triggers have been used for prophylactic and therapeutic platelet transfusions. For prophylactic platelet transfusion an increasing body of evidences suggests that a transfusion trigger of 10 x 10(9) per liter is appropriate for most clinical settings. In contrast, evidence for supporting a certain therapeutic transfusion trigger is lacking. Nevertheless, there is consensus that the platelet count should not be allowed to fall below 50 x 10(9) per liter in patients with acute bleeding. Another important aspect still pending of clear definition is the issue of the platelet dose to be transfused. It has been addressed by some small studies but a definite answer to this important clinical issue is, at least so far, still pending. The results of two ongoing trials, one sponsored by NIH through the Clinical Trials Network in Transfusion Medicine and Hemostasis and the other promoted by the BEST Collaborative Group are expected to help us to clearly defining the more effective and efficient way to transfuse platelet concentrates.     

Preliminary evaluation of optical glucose sensing in red cell concentrations using near-infrared diffuse-reflectance spectroscopy

Bacterial contamination of blood products is one of the most frequent infectious complications of transfusion. Since glucose levels in blood supplies decrease as bacteria proliferate, it should be possible to detect the presence of bacterial contamination by measuring the glucose concentrations in the blood components. Hence this study is aimed to serve as a preliminary study for the nondestructive measurement of glucose level in transfusion blood. The glucose concentrations in red blood cell (RBC) samples were predicted using near-infrared diffuse-reflectance spectroscopy in the 1350 to 1850 nm wavelength region. Furthermore, the effects of donor, hematocrit level, and temperature variations among the RBC samples were observed. Results showed that the prediction performance of a dataset which contained samples that differed in all three parameters had a standard error of 29.3 mg/dL. Multiplicative scatter correction (MSC) preprocessing method was also found to be effective in minimizing the variations in scattering patterns created by various sample properties. The results suggest that the diffuse-reflectance spectroscopy may provide another avenue for the detection of bacterial contamination in red cell concentrations (RCC) products.