[Control of the bacterial risk of transfusion in France in 2013]. / Maîtrise du risque bactérien transfusionnel en France en 2013.

Bacterial contamination of blood products (BP) remains the most important infectious risks of blood transfusion in 2013. Platelet concentrates (PC) are the blood products the most at risk, whether CPA or MCPS. In France, the residual risk has been steadily declining since 1994. For the platelets, the frequency of transfusion reaction due to bacterial contamination (TRBC) is now about at one per 50,000 CP distributed. The number of deaths has remained stable since 1994 with one death per year (300,000 distributed CP). The progressive decrease in the number of cases of TRBCs is the result of steady improvement of practices and prevention methods at all stages from collection to the transfusion of BP. But if all these improvements have significantly reduced the incidence of TRBCs, mortality is not changed with the CP and the reduction of this risk is a priority for the French Blood Establishment (EFS). Detection methods of CP contaminated or pathogen inactivation are two approaches available and can provide a significant reduction (for the former) or deletion (for seconds) of the risk of transfused contaminated CP. Currently, the choice is in favor of the detection of bacteria. New detection "rapid tests" methods were added to the panel of candidates and are being evaluated. Inactivation of pathogens remains the safest prospect of eliminating this adverse effect of transfusion. Implementation of one method for bacterial detection is probably a transitional measure.

[Prevention of bacterial risk: pathogen inactivation/detection of bacteria]. / Prévention du risque bactérien: inactivation des pathogènes/détection des bactéries.

Bacterial contamination of blood products remains the most important infectious risk of blood transfusion in 2013. Platelet concentrates (PC) are in cause in the majority of the transfusion reaction due to bacterial contaminations. A lot of prevention methods have been developed over the last 10 years (pre-donation interview, skin decontamination, diversion of the first 30 mL of the donation, leuko-reduction...), they have focused on limiting the contamination of the donations and prevent the bacterial growth in donations and/or in the blood products. These measures were effective and led to significantly reducing the risk of adverse effects associated with bacterial growth. However, every year there are about six accidents (with a high level of imputability) and one death. The reduction of the bacterial risk remains a priority for the French Blood Establishment (EFS). The procedure for skin disinfection is going to be improved in order to further strengthen this crucial step to avoid the contamination of donation. Methods of pathogen inactivation applied to plasma and PC are available in France and their effectiveness is demonstrated on the bacterial risk. Methods for bacterial detection of PC are used in many countries now. Automated culture is the most common. Alternatives are now available in the form of rapid tests able to analyze the PC just before the delivery and avoid false negatives observed with automated culture. Assessments are under way to confirm these benefits in 2013.

[Evolution of techniques for preparation of labile blood products (LBP): pathogen inactivation in LBP]. / Evolution des techniques de préparation des produits sanguins labiles (PSL): inactivation des pathogènes dans les PSL.

The techniques for inactivation of pathogens in labile blood products (LBP) would appear to be the new strategy which will permit us to increase transfusion safety in the face of the risks of transmission of pathogenic agents by LBP. Various methods are in the course of development or already validated and used in France. The latter only apply however to plasma or platelet concentrates. The mechanisms of action and the efficacy of inactivation and attenuation of pathogenic agents vary with the different techniques. Each of these constitutes a preparative procedure composed of unit steps which have to be fully mastered in order to ensure the quality and transfusion efficacy of the treated product.

[Automation in the preparation of labile blood products]. / Automatisation de la préparation des produits sanguins labiles.

The preparation of labile blood products in a blood bank is in permanent technological progress. Many operations, such as blood centrifugation, components separation, etc. are now performed by automated devices. A new generation of equipments is able to prepare blood products by reducing the number of manual operations. Therefore, buffy-coat platelet concentrate preparation and whole blood preparation can be prepared by these automated systems. Consequently, this directly impacts working conditions of employees, quality of blood products and process management.

[Bacterial detection leading to pathogen inactivation]. / De la détection bactérienne à l'inactivation des pathogènes.

Bacterial contamination of blood components remains the highest infectious risk in blood transfusion, the risk is particularly high when it affects platelet concentrates (PC). In France, the residual risk of transfusion reaction due to bacterial contamination of PC has been decreasing slowly since 1994 but for all severity 1 case occurs with about 25,000 distributed PC and one death occurs with 200,000 distributed units. This reduction of the risk may be due to the measures which were implemented during the last 10 years in order to prevent contamination during donation. Improving strategies for reducing the risks of bacterial contamination is one of the priorities of the French National Blood Transfusion Service (l'Etablissement Français du sang - EFS). The main target remains PC. Bacterial detection or pathogens inactivation are now available and are able to reduce (for detection) or prevent (for inactivation) the occurrence of reaction due to bacterial contamination of PC. Up to now, the choice is in favour of bacterial detection. A national study was carried out in seven regional EFS at the end of 2004. It aims at confirming the feasibility of a systematic bacterial screening of PC before their delivery. The first conclusions show that this screening can be implemented with acceptable modifications in term of platelets availability. We can expect in a next future that new pathogens reduction technique and/or new detection systems will be available, certainly more efficient to prevent reaction due to bacterial contamination. Implementation of actual detection methods is probably a temporary solution.

[Transfusion-transmitted bacterial infection: residual risk and perspectives of prevention]. / Transfusion et bactéries: risque résiduel et perspectives de prévention.

Bacterial contamination of blood components represents today the highest infectious risk of blood transfusion, the risk is particularly high when it affects platelet concentrates. The residual risk of transfusion reaction due to bacterial contamination of platelets concentrates remains stable. For all severity 1 case occurs with 25,000 distributed platelets concentrates and 1 death occurs with 200,000 distributed units. In France, efforts have focused on the prevention of contamination during donation--involving measures such as rejecting the first few millilitres of donated blood and improving skin disinfection--and the prevention of bacterial proliferation in platelets concentrates--notably by removing leukocytes and ensuring high-quality storage of donated blood. Improving strategies for reducing the risks of bacterial contamination is one of the priorities of the French National Blood Transfusion Service (l'Etablissement français du sang-EFS). There is currently considerable debate about the relative importance of bacterial screening methods and methods for inactivating pathogens present in PC. Automated culture (Biomérieux) and the ScanSystem (Hemosystem) and BDS (Pall) method are the most advanced detection systems available, to our knowledge. In term of pathogen inactivation system for platelets, Intercept (Baxter) is nearing the commercial market. These new prevention have logistic and/or functional consequences that will require close scrutiny methods. A national study group is currently considering the consequences of each of these methods and should give its opinion at the end of the first half of 2003.

Quality assessment of seven types of fresh-frozen plasma leucoreduced by specific plasma filtration.

BACKGROUND AND OBJECTIVES: A study was undertaken to determine plasma quality after specific filtration. MATERIALS AND METHODS: Seven types of plasma were tested, after filtration of plasma from filtered or non-filtered whole blood. Leucocyte counting was carried out after a 30-fold concentration of the sample. Twenty-nine parameters (including coagulation testing, proteins, coagulation factors and activation markers) were measured before and after filtration, and after 6 months of storage. RESULTS: After specific plasma filtration, the average residual leucocyte counts were less than 2250/l. In spite of small statistically significant changes in proteins, coagulation factors and complement activation, this study showed that plasma filtration did not alter plasma quality. After 6 months of storage at -30 degrees C, factor VIII recovery varied between 91 and 109%. Haemostasis parameters and activation markers remained within the normal range. CONCLUSIONS: Specific plasma filtration reduced the leucocyte number to < 104 leucocytes/l. The quality of plasma was not altered by the additional step of specific plasma filtration.

[Detection of bacterial contamination in platelet concentrates: perspectives]. / Dépistage des bactéries dans les concentrés de plaquettes: perspectives.

Bacterial contamination of blood components represents today the highest infectious risk of blood transfusion, the risk is particularly high when it affects platelet concentrates. In France the prevention methods developed over the past six years (donor selection, phlebotomy site preparation, first 30 ml diversion, systematic leuko-reduction...) aimed at limiting the introduction of bacteria in blood and bacterial proliferation. Several methods have been tested for the detection of bacterial contamination in platelet concentrates but none have been generalised. Difficulties were met, due to the necessity of 1) detecting only the platelet concentrates presenting a real infectious risk, when the presence of bacteria is observed in 2.2% (2-4%) of donated blood and 2) guaranteeing the availability of platelet concentrates. New methods have been developed which seem able to bring responses to these difficulties. Several processes are being (or will be) assessed, including automated blood culture, bacterial genomic detection with or without amplification, flow cytometric methods. In parallel, an indirect method able to detect the presence of bacteria, based on oxygen consumption, will also be evaluated. One (or several) of these processes should allow, in the short-term, to detect platelet concentrates presenting an infectious risk. In the future, the interest of bio-chips for bacterial detection in biological fluids must be investigated.

Plateletpheresis concentrates produced with the COMTEC cell separator: the French experience.

The latest generation of cell separators such as Trima (Gambro), Amicus (Baxter) and AS-TEC 204 (Fresenius), allow the collection of leucocyte-reduced platelet concentrates without secondary filtration. Fresenius has recently developed the COMTEC cell separator whose performance has been evaluated by several teams in France. This new cell separator is an improved version of the Fresenius AS-TEC 204 cell separator, designed to allow more efficient platelet collections. This study reports on the experience of six French teams (from Bordeaux, Clermont-Ferrand, Creteil, Dijon, Lille and Nancy) who obtained 696 leucocyte-reduced plateletpheresis concentrates in the course of collection using the new Fresenius COMTEC cell separator. All healthy volunteer donors fulfilled French selection criteria for platelet apheresis. Donors were eligible if they had suitable venous accesses, if their bodyweight was *50 kg and if their pre-apheresis platelet count was >150 x 10(9) l(-1). Between 4606 and 5229 ml of blood were processed. The mean volume of the platelet concentrates was between 439 and 493 ml (mean 460 +/- 63 ml). The platelet yield was of the order of 5.18 +/- 1.02 x 10(11) with only one platelet concentrate below the norm of 2 x 10(11) platelets (0.91 x 10(11)). No plausible explanation for this was found. The residual leucocyte levels conform to current norms. The platelet concentrates contained less than 1 x 10(6) leucocytes per concentrate (mean 0.233 +/- 0.150 x 10(6) leucocytes) in more than 97% of the components produced with >95% statistical confidence. The efficacy of the cell separator (52.44 +/- 7.35%) is comparable to that of other separators. The Fresenius COMTEC cell separator makes it possible to obtain leucocyte-reduced platelet concentrates which comply with current standards both in terms of platelet content and residual leucocyte level.

[Surveillance of biocontamination of the environment of labile blood products: its role in a quality assurance program]. / Suivi de la biocontamination de l'environnement des produits sanguins labiles: place dans une démarche d'action qualité.

As part of a quality assurance approach aiming at reducing the risk of bacterial contamination of labile blood components (BC), their environment was submitted to a twofold quality control. A yearly control was carried out by the University Hospital Laboratory of Hygiene (UH-LH). Another control was regularly implemented by our Quality Control Laboratory. In accordance with this quality system, we focused our attention on decontamination procedures, control targets and the definition of an acceptable threshold. The analysis of results over 1 year showed that they can be considered as satisfactory when less than 40 CFU/100 cm2 are found. Quality sheets were developed, aimed at motivating our staff, adapting the decontamination procedures and initiating corrective measures. This quality programme allowed us to develop close collaboration links with the UH-LH and to play a role in the prevention of hospital-acquired infections.

Validation of a simple method to count very low white cell concentrations in filtered red cells or platelets.

The increased performance of white cell (WBC) filters makes it difficult to count precisely the number of residual WBCs. Concentrations as low as 0.01 WBC per microL cannot be determined with electronic cell counters, conventional hemocytometers, or the flow cytometric techniques currently being used. This article describes a simple, manual method using a Nageotte hemocytometer with a large-volume chamber (50 microL) to count the number of WBCs contained in red cell (RBC) suspensions (preparations A, B, and C) and in platelet suspensions (preparation D) diluted 1 in 10 pure, or concentrated two fold. To validate the method, several reference ranges, prepared by successively adding mononuclear cells to a suspension of pure RBCs or platelets, were used. Among the different series, validation ranges varied from 0.2 to 12 to 0.01 to 0.5 WBCs per microL and correlation coefficients ranged from 0.929 to 0.996. To determine the limit of accurate detection, accuracy tests (n = 160) were carried out by two experienced operators on samples with WBC concentrations of about 5, 10, and 120 times the concentration at the theoretical limit of detection (1 WBC/chamber). No significant difference was observed in the various types of preparations (A, B, C, D) in the tests performed by the two operators. However, intra-assay coefficients of variation were 18, 9.5, and 2.2 percent, respectively, at WBC concentrations of 5, 10, and 120 times that at the theoretical limit of detection. These observations show that a limit of accurate detection (10%) seems to be reached when 10 cells are observed in a Nageotte hemocytometer.(ABSTRACT TRUNCATED AT 250 WORDS)