Bacterial contamination of blood components: Norwegian strategies in identifying donors with higher risk of inducing septic transfusion reactions in recipients

Bacterial contamination of blood and its cellular components remains the most common microbiological cause of transfusion associated morbidity and mortality, even in developed countries. This yet unresolved complication is seen more often in platelet transfusions, as platelet concentrates are stored at room temperature, in gas permeable containers with constant agitation, which support bacterial proliferation from relatively low undetectable levels, at the beginning of storage time, to relatively high virulent bacteria titers and endotoxin generation, at the end of shelf life. Accordingly, several combined strategies are introduced and implemented to at least reduce the potential risk of bacterial contaminated products for transfusion. These embody: improved donors arms cleaning; bacterial avoidance by diversion of the first portion of collection; reducing bacterial growth through development of newer storage media for longer platelet shelf life; bacterial load reduction by leucoreduction/viral inactivation, in some countries and eliminating the use potentially contaminated units through screening, through current available testing procedures, though none are not yet fully secure. We have not seen the same reduction in bacterial associated transfusion infections as we have observed for the sharp drop in transfusion associated transmission rates of HIV and hepatitis B and C. This great viral reduction is not only caused by the introduction of newer and more sensitive and specific detection methods for different viruses, but also the identification of donor risk groups through questionnaires and personal interviews. While search for more efficient methods for identifying potential blood donors with asymptomatic bacteremia, as well as a better way for detecting bacteria in stored blood components will be continuing, it is necessary to establish more standardized guidelines for the recognition the adverse reactions in recipients of potentially contaminated units. Efforts also should be also directed to identify blood donors with significant risk of bacteremia, at the time of donation in the first place as a high priority. The goal of this review is to highlights strategies for identifying both the sources of bacterial contamination of blood components in Norway and identifying donors with a higher risk of bacteremia at the time of donation. The key to achieving this goal is initiating continual revising and upgrading the Norwegian transfusion guidelines, based on the transfusion legislation and by introducing a relevant specialized donor bacterial questionnaire.     

Repeat subculture of known positive blood cultures: costly and ineffective in detecting polymicrobial bacteremias

Reincubation and subsequent subculture at 72 h of previously positive blood cultures failed to demonstrate an increase in detection of polymicrobial bacteremia as has been previously reported. These procedures increased the cost of blood cultures between 140-192% without yielding new organisms. No new information was gained in 94.7% of cultures and, in 11.1% of the cultures, less information was obtained either because the cultures were sterile or because the original organisms could not be reisolated.     

Operational criteria for adverse drug reactions in evaluating suspected toxicity of a popular scabicide

A recently developed algorithm for the diagnosis of adverse drug reaction (ADR) was used to investigate the quality of evidence in reported cases of ADRs to 1% gamma benzene hexachloride (GBH), a popular scabicide and pediculicide currently under suspicion as a cause of central nervous system (CNS) toxicity, especially in children. Of the 53 reported cases of alleged toxicity, 37 were associated with lindane insecticide (greater than 1% GBH), which is not a pharmaceutical preparation. Of these 37 cases, 34 scored as definite or probable reactions on the algorithm. Of the 26 reports associated with the drug, 1% GBH, none scored as definite and only 6 as probable ADRs. Of these 6 probable cases, 5 represented inappropriate application or unintended ingestion. The use of rigorous operational criteria, such as those developed in this algorithm, permits a scientifically disciplined assessment of whether or not a drug has been fairly indicted, and also provides valuable clinical information about other aspects of suspected drug toxicity.     

The BEST Working Party of the International Society of Blood Transfusion: an international effort to improve the quality of blood components

BACKGROUND: The Biomedical Excellence for Safer Transfusion (BEST) Working Party of the International Society of Blood Transfusion was formed with the aim of improving the quality and safety of blood components. An outline of the aims, working methodology, and results after the first 4 years of activity of the BEST Working Party is presented. RESULTS: Seven studies have been performed, evaluating techniques for counting residual white cells in white cell-reduced red cells, platelet quality control, and cellular harvests in blood components prepared with different methods. Areas of possible interest in the near future include stem cells, platelet crossmatching, and virus inactivation of blood components. An important BEST feature is the sharing of information gathered through collections of large sets of data from routine settings, so as to produce a reliable picture of the "real world." CONCLUSION: Such information could prove useful to those in charge of developing recommendations and guidelines.     

血液病急诊患者输注成分血的护理风险管理

目的:提高护理人员风险管理意识,降低血液病急诊患者输注成分血的护理风险。方法:通过培养护理人员对风险的识别及评估能力,提高护理人员的风险管理意识,对风险事件高危人群、风险事件易发环节加强管理,增强了护理人员对急诊患者输注成分血的风险处理能力。结果:运用有效的护理风险管理方法,对2006年1～6月份急诊481位不同年龄,不同类型血液病患者1354例次输注成分血实施护理风险管理,未发生护理风险事件。问卷调查患者满意率为97%以上。结论:实施风险管理可以减少风险事件的发生,以及风险事件对患者和医院造成的危害及经济损失,从而提高护理质量。     

Comparison of acute non-haemolytic transfusion reactions in female and male patients receiving female or male blood components

To study the relationship between antibodies detected in patients' and/or donors' sera and the clinical features of acute non-haemolytic transfusion reactions (ANHTRs), and to determine any gender-related difference. ANHTRs range from urticaria to transfusion-related acute lung injury (TRALI). Antibodies to human leukocyte antigen (HLA), granulocytes, platelets, and/or plasma proteins are implicated in some of the ANHTRs. A higher antibody positivity is expected for females than for males. A comparative study of ANHTRs for antibody positivity and their clinical features between females and males for both patients and donors is helpful for characterizing ANHTRs including TRALI more clearly, but such studies are few and outdated. Two hundred and twenty-three ANHTR cases reported by 45 hospitals between October 2000 and July 2005 were analysed. The patients and 196 donors of suspect blood products were screened for antibodies to HLA Class I, HLA Class II, granulocytes, and platelets. The patients were also screened for anti-plasma protein antibodies. The types and severity of ANHTR did not differ significantly between female and male patients. The frequency of the anti-HLA antibodies, but not that of the non-HLA antibodies, was significantly higher in females. Non-HLA antibodies were significantly associated with severe reactions in females. All the TRALI cases had predisposing risk factors for acute lung injury, and 60% of the cases showed anti-leucocyte antibodies. Although the anti-HLA antibodies were detected more frequently in females than males, no significant association of ANHTRs including TRALI with gender, not only for patients, but also for donors, could be shown in this study.     

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.     

Universal leukodepletion of blood components results in a significant reduction of febrile non-hemolytic but not allergic transfusion reactions.

BACKGROUND: Universal leukodepletion of blood components to prevent acute non-hemolytic transfusion reactions (NHTRs) is still a subject of debate. PATIENTS AND METHODS: Transfusion-associated NHTRs observed at our hospital in the last 6 years were retrospectively analyzed. Buffy-coat depleted red blood cells (bc-RBCs), and if indicated, leucodepleted post-storage (ld-RBCs) were initially used. In April 1997, universal leukodepletion was implemented at our hospital, and thereafter only prestorage ld-RBCs were used. All platelet concentrates transfused during this time were prestorage filtered single-donor apheresis platelets (SDAPs). RESULTS. A total of 163,090 blood products were transfused from April 1995 to April 2001 (bc-RBC: n=34,040 units; ld-RBC: n=66,967; SDAP: n=14,516; FFP: n=47,567). The number of post-transfusion febrile NHTRs occurring with each blood product was 65 (0.19%) for bc-RBCs, 8 (0.16%) for post-storage ld-RBCs, 16 (0.03%) for prestorage ld-RBCs, 16 (0.11%) for SDAPs, and 10 (0.02%) for FFP. Allergic reactions (n=116) were most frequently observed after SDAP transfusion (0.32%) and occurred at a similarly low rate after transfusion of all other blood components (0.03-0.08%). CONCLUSION: In conclusion, acute NHTRs rarely occur after the use of leukodepleted blood components. Prestorage appears to be more effective than post-storage leukodepletion in preventing febrile reactions following a blood transfusion.     

无偿献血人群HCV感染的检测和输血残余风险分析

目的了解深圳地区无偿献血人群HCV感染状况,评估血液经EIA筛查抗-HCV后经血传播HCV感染的残余风险。方法采用两种EIA试剂对献血者血液进行抗-HCV筛查,采用核酸检测技术检测EIA检测"合格"标本中HCV RNA,对HCVRNA阳性标本进行荧光定量PCR检测病毒载量,并对PCR扩增产物进行测序和病毒基因亚型分析。结果共筛查1997～2009年期间的献血者254 570人份,发现抗-HCV阳性1401人份,阳性率为0.55%;对2002～2007年期间EIA检测"合格"的113639份献血者血液标本进行NAT检测,检测出1份HCV RNA阳性、抗-HCV阴性的血清转换窗口期感染的献血者血液,HCV残余风险高达1/113 639。结论 EIA筛查后血液安全性有了很好的保障,但由于HCV感染窗口期存在,经血传播HCV残余风险依然处于较高的水平,NAT应用对提高血液安全,降低输血传播HCV残余风险意义重大。     

无偿献血人群HCV感染的检测和输血残余风险分析

目的了解深圳地区无偿献血人群HCV感染状况,评估血液经EIA筛查抗-HCV后经血传播HCV感染的残余风险。方法采用两种EIA试剂对献血者血液进行抗-HCV筛查,采用核酸检测技术检测EIA检测＂合格＂标本中HCV RNA,对HCVRNA阳性标本进行荧光定量PCR检测病毒载量,并对PCR扩增产物进行测序和病毒基因亚型分析。结果共筛查1997～2009年期间的献血者254 570人份,发现抗-HCV阳性1401人份,阳性率为0.55%;对2002～2007年期间EIA检测＂合格＂的113639份献血者血液标本进行NAT检测,检测出1份HCV RNA阳性、抗-HCV阴性的血清转换窗口期感染的献血者血液,HCV残余风险高达1/113 639。结论 EIA筛查后血液安全性有了很好的保障,但由于HCV感染窗口期存在,经血传播HCV残余风险依然处于较高的水平,NAT应用对提高血液安全,降低输血传播HCV残余风险意义重大。     

流式细胞术在成分血残留白细胞检测中的应用

目的 探讨流式细胞术(FCM)绝对计数法在成分血残留白细胞检测中的应用价值。方法 采用FCM绝对计数法检测不同稀释度的浓缩血小板样本中自细胞残留量，并与Nageotte血细胞计数板法比较。结果 两种方法计数微量白细胞具有高度相关性(r=0．9964，P＜0．001)。低浓度白细胞计数时，FCM法变异系数小于Nageotte计数板法。两种方法检测结果相比，Nageotte计数板法计数值偏低。结论 流式细胞术绝对计数法具有快速、客观、精确和重复性好等优点，是一种稳定的检测成分血中微量残存白细胞数的方法。     

Leukocyte-reduced blood components in transfusion medicine. Current indications and prospects for the future.

Transfusion medicine is a rapidly evolving specialty, and efforts are ongoing to improve the safety and quality of blood component therapy. Leukocytes are known to be the cause of numerous adverse effects of transfusion therapy, and their removal from red cells and platelet components may be desirable in a variety of clinical settings. The various complications of transfusion that can be attributed to contaminating leukocytes and the benefits of leukocyte depletion are addressed in this article. Laboratory as well as clinical data are summarized.