Limited utility of algorithms predicting blood transfusions.

BACKGROUND: Prediction of transfusion is presumed to reduce wastage rates in pre-operative autologus blood donation (PABD) and unnecessary providing and cross-matching in allogeneic transfusion. The clinical utility of published algorithms in predicting transfusions was analysed. MATERIALS AND METHODS: In a cohort of 195 patients undergoing total hip arthroplasty, after PABD, expected transfusion needs were predicted with two published algorithms (A and B). The algorithms were then compared to actual transfusions. Assumptions and formulae of these algorithms were varied in an attempt to improve their prognostic utility. RESULTS: The optimal variation of A resulted in allogeneic transfusions (PABD setting) or uncross-matched transfusions (allogeneic setting) of 27.3%, and a wastage rate of autologous units or unnecessary cross-matching of 73.8%, compared to 33.3% and 76.6%, respectively, for the original algorithm. The original version of algorithm B resulted in (allogeneic) transfusions of 78.8%, and a wastage rate or unnecessary cross-matching of 46.2%. The former could be improved by a variation of the algorithm to 69.7%. Comparing the optimal variations of both algorithms, the more elaborate algorithm A reduced overall transfusion risk significantly better (P =0.001). The two algorithms were not statistically different in reducing resource consumption (P =0.09). DISCUSSION: Although the prognostic utility of algorithm A was significantly better for reducing overall transfusion risk, both algorithms were unable to meaningfully identify patients who would benefit from PABD or cross-matching. The algorithms could not increase the percentage of PABD patients transfused, or the percentage of cross-matched patients transfused in the allogeneic setting. Furthermore, they could neither reduce transfusion risk nor resource consumption.

Deformability of Red Blood Cells and Correlation with ATP Content during Storage as Leukocyte-Depleted Whole Blood.

BACKGROUND: Storage duration of red cells has been associated with increased morbidity and mortality following transfusion. This association has been attributed to the loss of deformability of stored red cells leading to deterioration of microvascular perfusion. ATP content is considered a critical determinant of the deformability of stored red cells. METHODS: ATP content and deformability were determined after storage for up to 49 days in 40 leukocyte-depleted whole blood units. Red cell deformability was determined using a laser-assisted optical rotational cell analyzer (LORCA( (®) )) employing shear stress (SS) ranging from 0.3 to 30 Pa. Deformability was expressed as the elongation index (EI). EI was correlated with ATP content. RESULTS: ATP content decreased from 3.5 to 1.7 ?mol/g hemoglobin. EI increased from 0.03 to 0.05 at an SS of 0.3 Pa, and decreased from 0.62 to 0.59 at an SS of 30 Pa. Correlation coefficient (r) of ATP vs. EI at 0.3 Pa ranged from -0.17 to +0.15 during storage. At 30 Pa, r ranged from -0.03 to +0.45. Correlation increased with storage irrespective of SS, and increased with SS irrespective of storage. CONCLUSIONS: ATP content is not a valid surrogate marker for red cell deformability and may not reflect in vivo survival of stored red cells.

The Platelet Function Analyzer (PFA-100) as a Screening Tool in Neurosurgery.

We investigated whether the inclusion of the PFA-100 in the preoperative screening of neurosurgical patients might reduce perioperative bleeding complications. Patients with intracranial space-occupying lesions who were scheduled for neurosurgery underwent routine preoperative PFA-100 testing. In case of an abnormal PFA test, patients received prophylactic treatment with desmopressin. 93 consecutive patients were compared to 102 consecutive patients with comparable characteristics operated before introduction of the PFA-100 testing. 2 patients (2.2%) in the PFA group and 2 patients (2.0%) in the non-PFA group experienced clinically relevant intracranial bleeding confirmed by computed tomography (OR 1.05, 95% CI 0.39-2.82; P = 1.0). Transfusions were not significantly different between the two groups. 13 (14.0%) patients in the PFA group and 5 (4.9%) patients in the non-PFA group received desmopressin (OR 3.2, 95% CI 1.1-9.2; P = 0.045). Preoperative screening with the PFA-100 did result in a significant increase in the administration of desmopressin, which could not reduce perioperative bleeding complications or transfusions.

The influence of maintaining the correct whole blood-to-anticoagulant ratio during donation on the quality of leukoreduced whole blood.

BACKGROUND: It is unclear whether maintaining the correct whole blood-to-anticoagulant (WB : AC) ratio during collection can improve the quality of red blood cell (RBC)-containing blood products to a clinically relevant degree. STUDY DESIGN AND METHODS: A total of 2 × 20 CPDA-1 leukoreduced whole blood (WB) units suspended in CPDA-1 were investigated. In one group, AC was continuously added to the donated blood, maintaining the correct WB : AC ratio during collection, using a new drawing device (MacoPharma ABC). In the other group, WB units were produced conventionally. Adenosine triphosphate (ATP), 2,3-diphosphoglycerate, free hemoglobin (Hb), potassium, glucose, lactate, pH, and variables of coagulation were determined on Days 1, 7, 21, 35, 42, and 49 of storage. Variables of RBC deformability and aggregability were determined using a laser-assisted optical rotational cell analyzer. RESULTS: The ABC and conventional group showed comparable unit volumes of 525 (SD, 5.3) mL versus 524 (SD, 10.2) mL and Hb content of 65.9 (SD, 5.1) g/unit versus 67.5 (SD, 7.8) g/unit, but higher variation after conventional blood drawing (p = 0.006 and p = 0.07, respectively) was observed. During storage, none of the measured quality variables were significantly different between the groups. Mean (SD) ATP was 2.33 (0.41) µmol/g Hb versus 2.24 (0.39) µmol/g Hb after 42-day storage. Deformability was not different (p = 0.44), whereas the extent of the aggregability was higher in the conventional group (p = 0.04). CONCLUSION: The ABC device provided a better standardized blood product but did not improve RBC storage variables or plasma quality. It slightly reduced RBC aggregability during storage. Excess AC at the beginning of a donation appears not to significantly affect RBC storage in conventional blood drawing.

Diagnosis and therapeutic management in a patient with type 2B-like acquired von Willebrand syndrome.

Acquired von Willebrand syndrome (AVWS) usually mimics von Willebrand disease (VWD) type 1 or 2A. However, in rare cases, the characteristics of other VWD types can predominate in AVWS that might require careful consideration of differential treatment options. The diagnosis and the treatment of a case of type 2B-like AVWS are discussed. Diagnosis of AVWS was ascertained by determining ristocetin cofactor activity, ristocetin-induced platelet aggregation, von Willebrand factor antigen, collagen binding and characterization of von Willebrand factor (VWF) multimers. Inhibitor presence was sought through mixing experiments, the Bethesda method, and calculation of the in-vivo recovery and plasma half-life of VWF after administration of factor VIII/VWF concentrate. Mutations in the A1 domain of VWF were ruled out by sequencing of exon 28 of the VWF gene. A 34-year-old male patient, putatively diagnosed with type 2B VWD, and undergoing laparoscopic cholecystectomy, did not respond adequately to perioperative hemostatic treatment with desmopressin and high doses of factor VIII/VWF concentrate, requiring the administration of recombinant activated factor VII. Further diagnostic workup revealed AVWS mimicking type 2B VWD, most likely owing to an autoantibody developed in the course of underlying monoclonal gammopathy of undetermined significance. The presence of AVWS should be considered before a diagnosis of type 2B VWD is made, especially in patients with a history atypical for inherited disease.

Influence of different hydroxyethyl starch (HES) formulations on fibrinogen measurement in HES-diluted plasma.

BACKGROUND: Fibrinogen is the first coagulation factor becoming critical in dilution coagulopathy. Volume replacement in major blood loss is performed with large volumes of crystalloid and colloid solutions. The latter has been shown to compromise accurate photo-optical measurement of fibrinogen. This study determined the influence of different hydroxyethyl starch (HES) formulations. METHODS: Citrated plasma samples of 8 healthy volunteers were diluted by 30% or 50% with either HES 10% (200/0.5; HES-200), HES 6% (70/0.5; HES-70), or HES 6% (450/0.7; HES-450). Fibrinogen concentrations were determined by photo-optical measurement (Behring coagulation system [BCS]: derived fibrinogen, or Clauss fibrinogen, calibrated for high [CLS] or low fibrinogen concentrations [CLS-low]) as well as mechanical end point determinations (KC4: CLS-KC4). Measured values were compared with calculated values. RESULTS: On average and across all photo-optical methods, fibrinogen concentrations were overestimated, particularly with HES-200. Hydroxyethyl starch-70 and HES-450 did not differ much from each other. Overestimation was relatively greater for 50% dilutions with all HES formulations. Surprisingly, overestimation was most prominent with CLS-low, the method supposed to most reliably measure low fibrinogen concentrations; overestimation amounted to 92% and 120% with HES-200, 54% and 73% with HES-70, and 51% and 79% with HES-450, for 30% and 50% dilutions, respectively. In contrast, CLS-KC4 always yielded sufficiently accurate results. CONCLUSIONS: The study showed that all HES solutions more or less impaired the fibrinogen measurement with the photo-optical method. In particular, overestimation with CLS-low may prevent timely fibrinogen replacement in major blood loss. Hydroxyethyl starch concentration appears to be more relevant for this effect than its molecular size.

Photo-optical methods can lead to clinically relevant overestimation of fibrinogen concentration in plasma diluted with hydroxyethyl starch.

BACKGROUND: Adequate fibrinogen concentration is a crucial component of sufficient perioperative/posttraumatic hemostasis. In major blood loss, large volumes of fluids are being administered, which have been shown to interfere with valid determination of fibrinogen concentration. This may lead to wrong treatment decisions. We studied the variables that cause the discrepancies between measured and true fibrinogen concentrations in samples diluted with volume replacement fluids. METHODS: Citrated plasma samples of healthy volunteers were diluted by 30% and 50% with phosphate buffered saline (PBS), hydroxyethyl starch (HES) 10% (200/0.5), or gelatine (GEL). Fibrinogen concentrations of diluted samples were derived from the prothrombin time (PT) and the Clauss method (CLS) was applied. With the latter, several modifications and combinations of detection principles and thrombin reagents were investigated. Values were compared with ''true,'' that is, calculated values based on the results of undiluted samples for each method. RESULTS: Photo-optical methods resulted in significant overestimation of the fibrinogen concentration in blood diluted with HES, depending on the thrombin reagent used. This was particularly true for modifications of the CLS aimed at measuring low fibrinogen concentrations. Use of another thrombin reagent gave satisfactory results for this modification. The validity of mechanical end point determination methods was considered sufficient and was not influenced by the use of different thrombin reagents. CONCLUSIONS: Fibrinogen determination methods used in situations of major blood loss need to be validated with samples containing significant amounts of volume replacement fluids, particularly colloids. Only some combinations of test principle, detection method, and reagents will give valid results.

Leukodepletion of autologous whole blood has no impact on perioperative infection rate and length of hospital stay.

BACKGROUND: Several mechanisms have been proposed as possible causes of transfusion-related immunomodulation (TRIM) after allogeneic transfusion. If one of these mechanisms, the release of mediators of immunity and inflammation ("biologic response modifiers"[BRMs]) from disintegrating blood cells during storage of blood products, really causes TRIM, it should in principle also occur after autologous transfusion. As a consequence, prestorage leukoreduction of autologous blood should be able to prevent the clinical consequences of TRIM after autologous transfusion. STUDY DESIGN AND METHODS: This hypothesis was investigated in a multicenter, double-blind, randomized controlled trial. A total of 1089 patients scheduled for total hip arthroplasty and eligible for preoperative autologous blood donation were randomly assigned to receive autologous whole blood (AWB) either unmodified or leukoreduced when transfusion was indicated. RESULTS: Neither the primary study outcome, that is, the overall postoperative infection rate (17.3% vs. 17.6%, p = 0.59), nor several secondary outcomes like median length of hospital stay (14 days vs. 14 days, p = 0.17) were significantly different between groups, whether analyzed according to the intention-to-treat principle or "as treated." CONCLUSION: This trial provides strong evidence, from clinically relevant outcome data, that leukoreduction of AWB does not improve postoperative patient outcome and that the release of BRMs from disintegrating blood cells during storage cannot explain the immunomodulatory effect of blood transfusion.

Atrial natriuretic peptide serum concentration decreases in donors undergoing discontinuous plasmapheresis involving a large extracorporeal blood volume.

BACKGROUND: In donor plasmapheresis, circulatory reactions occur at a similar frequency as in whole-blood donation although the large extracorporeal blood volume (ECV) occurring during discontinuous plasmapheresis might predispose donors to hypovolemic reactions. The regulatory mechanisms compensating for this intradonation blood volume (BV) deficit are not well understood. It was the aim of this study to delineate whether atrial natriuretic peptide (ANP) is involved in the BV regulation of plasmapheresis donors. Because ANP regulates volume overload, it might decrease during BV decrease in plasmapheresis. STUDY DESIGN AND METHODS: ANP serum concentrations were determined in 60 donors undergoing discontinuous plasmapheresis. Samples were taken before the start of the procedure and when maximum ECV (ECV(max)) was reached at the end of the last withdrawal. Donors were randomly selected after stratification for sex and BV. In a control investigation, the same donors were kept in a reclined position for the duration of a plasmapheresis session without plasma withdrawal. ANP plasma concentration changes were correlated with changes of hemodynamic variables, which were recorded noninvasively with bioelectrical impedance cardiography. RESULTS: Median ANP concentration decreased from 13.0 to 8.4 pg per mL during donation and from 11.6 to 10.5 pg per mL during the control session. The mean control-adjusted ANP change due to plasma withdrawal was -2.62 pg per mL (p = 0.006). This decrease was not attributable to a dilution effect. ANP change did not correlate with changes of recorded hemodynamic variables. CONCLUSION: The decrease of the ANP serum concentration during plasmapheresis demonstrates that the ECV(max) constitutes a hypovolemic challenge of the donors, which elicits a neurohormonal regulatory mechanism aimed at maintaining cardiovascular homeostasis.

Diagnostic performance of the platelet function analyzer (PFA-100) for the detection of disorders of primary haemostasis in patients with a bleeding history-a systematic review and meta-analysis.

The Platelet Function Analyzer (PFA-100) is increasingly being used in the workup of patients with a bleeding diathesis. A profound knowledge of the possible diagnostic performance of this test is essential in order to make sound clinical decisions based on its results. It was the aim of this study to systematically review the published literature and provide valid estimates of the diagnostic performance of the PFA-100 for detecting disorders of primary haemostasis in newly presenting patients with a bleeding diathesis. A comprehensive literature search was performed for studies published between January 1994 and February 2006. Studies were eligible for the systematic review if they provided data supposed to be applicable to the determination of the diagnostic performance of the PFA-100. Furthermore, they were included in a meta-analysis if study reporting allowed calculation of sensitivity and specificity and if study quality ensured minimized biases of these estimates for the described clinical setting. Pooled weighted sensitivity, specificity and diagnostic odds ratio were calculated applying random effects modelling and constructing summary operator characteristic curves. This was done separately for the available test modifications using either collagen/epinephrine (PFA-EPI) or collagen/adenosine-diphosphate (PFA-ADP) for platelet activation. Thirty-six articles were included in the systematic review. Six studies met our eligibility criteria for a meta-analysis. The major reason for exclusion from the meta-analysis was a case-control design. A total of 1486 and 1259 patients were included in the meta-analysis of the diagnostic performance of the PFA-EPI and PFA-ADP, respectively. Pooled weighted sensitivity and specificity of the PFA-EPI/PFA-ADP in detecting a disorder of primary haemostasis were: 82.5/66.9% (95%-confidence interval (95%-CI): 76.0-88.9%/57.9-75.9%), and 88.7/85.5% (95%-CI: 84.3-93.1%/82.0-89.1%). 83/75% of patients with a positive PFA-EPI/PFA-ADP result do have a disorder of primary haemostasis whereas 88/79% with a negative PFA-EPI/PFA-ADP result do not. The PFA-EPI appeared to have a higher sensitivity and better predictive values than the PFA-ADP in detecting disorders of primary haemostasis, although a rigorous gold standard definition for a disorder of primary haemostasis, particularly for platelet disorders, was not applied in most studies. The majority of the studies lacked important requirements for quality and reporting, precluding a more precise and definitive characterization of the clinical utility of the PFA-100. This emphasizes the need for an evidence-based critical appraisal of diagnostic studies in haemostasis research in order to promote the conducting of studies that produce clinically relevant results.

Blood volume regulation in donors undergoing intermittent-flow plasmapheresis involving a high extracorporeal blood volume.

BACKGROUND: Intermittent-flow plasmapheresis (IFP) often involves a large extracorporeal blood volume (ECV) of donors during donation. Depending on equipment and donor characteristics, ECV can exceed 20 percent of a donor's blood volume (BV). It was the aim of this study to delineate mechanisms of BV regulation associated with these volume shifts. STUDY DESIGN AND METHODS: Parameters of BV regulation were recorded in 60 donors (30 men, 30 women) undergoing IFP, who were randomly selected after stratification for sex and BV. Shock index (SI), stroke volume (SV), cardiac index (CI), and thoracic fluid content (TFC) were determined at the beginning of the procedure and when maximum ECV (ECV(max)) was reached with noninvasive techniques. In a control investigation, donors were kept in reclined position for the duration of an IFP session without actually donating. RESULTS: SI increased significantly during IFP (+0.18; p < 0.0001). SV decreased significantly (-14.3 mL/stroke; p < 0.0001). CI did not decrease significantly (-0.07 L/min/m(2) body surface area; p = 0.33). Preservation of CI was due to a significant rise in heart rate (+13.4 beats/min; p < 0.0001). TFC decreased significantly during IFP (-0.77 kOmega(-1); p < 0.0001), indicating the development of an intravascular volume deficit. The changes of SI, heart rate, and TFC weakly correlated with ECV(max). CONCLUSION: The hemodynamic response during IFP is consistent with a hypovolemic challenge of the donors and is sufficient to maintain cardiac function. ECV(max) during donation does not reliably predict the degree of hypovolemic stress, as long as it remains below 20 percent. This might warrant reevaluation of collection limits based on ECV(max).

In-line filtration of autologous whole blood.

BACKGROUND: Experimental data suggest that autologous white blood cells (WBCs) might exert an immunomodulatory effect. Leukodepletion of autologous blood is considered to prevent this unwanted side effect of autologous transfusion. In some cases, however, prolonged filtration or filtration failures occur. Because such autologous units cannot simply be discarded, the interest was in the storage variables of autologous whole blood (AWB) units after prolonged filtration. STUDY DESIGN AND METHODS: AWB of patients undergoing orthopedic surgery was leukodepleted before storage or left unmodified. Filtration times, volume, WBC count, hemoglobin level, hemolysis, potassium, and ATP were determined in all units with filtration times of more than 60 minutes that had not been transfused by the time of expiry and in representative samples of units that had been filtered normally or that had not been filtered. RESULTS: In AWB filtration, the rate of prolonged filtrations or filter blockades is three to four times higher than in allogeneic whole-blood filtration. Filtration or prolonged filtration leads to a mean loss of red blood cell (RBC) mass of 7.3 or 18.2 percent, respectively. Even in units with filtration times of more than 3 hours, storage variables were not significantly different from normally filtered or unfiltered units. Filtration times showed a high intraindividual correlation. CONCLUSION: Leukodepletion of AWB results in a diminished preoperative deposit of RBCs that is pronounced in units with prolonged filtration. The quality of the latter suggests that it is not justified to discard AWB units with prolonged filtration times. Prolonged filtrations are related to patient characteristics that have yet to be defined.

Modern concepts of autologous haemotherapy.

The increasing current perception that the safety of allogeneic blood transfusion has dramatically been improved during the last decade is challenging autologous haemotherapy methods. In addition, growing concern about the unfavourable cost-effectiveness of most autologous haemotherapy methods requires a refinement of the application of these measures to well defined circumstances. In contrast, newly emerging transfusion-transmissible infections or periods of blood shortage might revive interest in these blood sparing techniques. Preoperative autologous blood donation still plays a significant role in settings with high individual benefit for the patient, high transfusion probabilities and when all opportunities of cost minimization can be applied. Preoperative plasmapheresis is considered to be a sensible adjunct if intraoperative retransfusion of salvaged and washed red cells is planned. Acute normovolaemic haemodilution is valuable when the patient's tolerability of the haemodilution and the expected blood loss are carefully examined beforehand. Intra- or postoperative salvage of wound blood can also be regarded as useful measures to prevent allogeneic transfusions as long as the specific advantages and disadvantages of the different methods are taken into account. Finally, alternative and supplemental measures such as iron or erythropoietin administration should always be considered in order to optimize the efficacy and effectiveness of autologous haemotherapy methods. The goal of a "bloodless medicine" might not be reached but is supposed to be approached closely with an integrated concept exploiting all measures available. However, in times of restricted health care resources, regular sound cost-effectiveness analyses, taking the availability and the current safety profile of allogeneic blood products into account, are always warranted and needed.

The effect of ASA on platelet activation during apheresis and on in-vitro properties of stored platelet concentrates.

BACKGROUND: Preventing the activation of PLTs may ameliorate (or mitigate) the PLT storage lesion (PSL), which encloses all structural and biochemical changes caused by collection, processing, and storage of PLT concentrates (PCs). Partial inhibition of PLT function due to ingestion of aspirin (ASA) by blood donors reduces the functional activity of the collected PLTs, however, by preventing premature PLT activation, it might reduce the PSL as well. STUDY DESIGN AND METHODS: In a randomized crossover study, 10 healthy donors donated two single-donor PCs (SDPCs) each, taking 500 mg ASA 12 hours before one of the aphereses (Group A) and taking no medication before the other donation (Group B). In-vitro tests of PLT function were performed in donors before and after apheresis and in SDPCs during storage (Days 1, 3, and 5). RESULTS: ASA ingestion resulted in a significant decrease of induced PLT aggregation in donors (p < 0.005) and SDPCs on Day 1 (p < 0.01). TRAP-6-induced expression of p-selectin (CD62p) was significantly reduced in Group A SDPCs only on Day 1 (p < 0.02). There were no significant differences of in-vitro function (LDH, lactate, pH, morphology score, CD62p expression, fibrinogen binding) between Group A and B (SDPCs and donors). Apheresis did not result in a significant activation of PLTs in donors or SDPCs. CONCLUSIONS: These limited data do not show a detectable beneficial effect of ASA ingestion on the PSL but do suggest that ASA ingestion before apheresis may not be detrimental to the clinical effectiveness of the stored product.

Extracorporeal blood volume of donors during automated intermittent-flow plasmapheresis and its relevance to the prevention of circulatory reactions.

BACKGROUND: Intermittent-flow plasmapheresis often involves a large extracorporeal blood volume of the donor during the procedure with the concomitant risk of circulatory reactions. Guidelines governing donor recruitment often apply an arbitrary threshold of 15 percent of the donors' blood volume not to be exceeded during hemapheresis procedures. No data demonstrating the suitability of this approach exist. STUDY DESIGN AND METHODS: The blood volumes of 1204 plasmapheresis donors were calculated with different formulae that utilized either body weight or body surface area. Extracorporeal blood volumes of these donors were determined for a commonly used intermittent-flow plasmapheresis machine known to result in a large extracorporeal blood volume. A validated model was employed that calculated the fluid volume shifts occurring during the procedure. The records of all plasmapheresis procedures of these donors were retrospectively reviewed for circulatory reactions. RESULTS: The median extracorporeal volumes ranged from 14 to 17 percent of the blood volume at a donor Hct level of 0.40 to 0.48 L per L for men and from 17 to 20 percent at a Hct level of 0.36 to 0.44 L per L for women. In more than 60 percent of male and more than 90 percent of female donors, extracorporeal volumes exceeded 15 percent of the blood volume during plasmapheresis. In this subgroup, 65 percent of male and 75 percent of female donors never presented with any signs of circulatory reactions. CONCLUSION: Application of an arbitrary threshold of 15 percent of the donors' blood volume not to be exceeded during hemapheresis procedures is expected to lead to an unjustified deferral rate in plasmapheresis donors.

Inline-filtration.

BACKGROUND: Routine leukocyte-depletion (LD) of cellular blood products, and even plasma, is currently being implemented in most European countries, as a result of the fear that the variant Creutzfeldt-Jakob-disease (vCJD) might be transmissible by transfusion. However, not only is the scientific evidence supporting such a notion scarce, but the benefits of applying this procedure to all patients also remain unfounded. METHODS: A MEDLINE-research for studies dealing with the indications for LD was performed. In addition, the guidelines and recommendations of national and international health authorities were scrutinized. RESULTS: To date,the only proven benefit of LD that can be applied to all patients is the reduction of non-hemolytic febrile transfusion reactions. In addition, LD reduces HLA-immunization and platelet refractoriness in multi-transfused patients. In immunocompromized patients, LD reduces transfusion-transmitted CMV-disease. Furthermore, a minority of 5-10% of transfusion-related-acute-lung-injury cases can be prevented by LD. However, the potential of reducing the immunomodulating effects of transfusion such as postoperative infection, cancer-recurrence-related or overall mortality and of reducing septicemia due to bacterial contamination is still at issue. AIDS patients do not benefit from LD, at least. The suitability of LD for preventing the transmission of vCJD is at best hypothetical. Potential risks of LD like increased leakages have not been taken into account adequately to date. CONCLUSIONS: At present, the scientific evidence does not justify the introduction of LD as a routine measure. In times of limited health care resources, this costly procedure might limit access to medical services with proven effectiveness and efficiency. In addition, the loss of 5-10% of the red cell pool is predicted to lead to more blood supply shortages than previously seen.