An estimate of the current risk of transmitting blood-borne infections through blood transfusion in Italy

We conducted a retrospective cohort study to estimate the incidence of major blood-borne agents among Italian blood donors and calculated the risk of infection among blood recipients using the 'incidence/window period model'. The study was conducted among 46 180 blood donors enrolled in six blood centres between 1994 and 1999. During follow-up, seven new infections were confirmed: three donors seroconverted for anti-human immunodeficiency virus (HIV); two for anti-hepatitis C virus (HCV); and two showed hepatitis B surface antigen (HBsAg) reactivity; no cases of syphilis were observed. The incidence rates per 100 000 person/years were: 4.06 (95% CI: 0.82-11.85) for HIV; 2.41 (95% CI: 0.29-8.70) for HCV; and 2.70 (95% CI: 0.32-9.77) for HBsAg; the incidence for total hepatitis B virus (HBV) infection was 9.77 per 100 000 person/years (95% CI: 1.16-35.36). The estimated risk of an infectious blood unit not being detected was: 2.45 (95% CI: 0.13-12.33) per 1 million units for HIV; 4.35 (95% CI: 0.30-22.39) for HCV; and 15.78 (95% CI: 1.16-84.23) for HBV. Overall, an estimated 22.58 per 1 million units are infected. In Italy, the risk of transfusion-transmitted infections is low and is similar to that in other western countries. The introduction of new more sensitive screening tests could reduce the residual risk of transfusion-transmitted infection by 40-80%.     

Residual risk of transfusion transmitted human immunodeficiency virus, hepatitis B virus, hepatitis C virus and human T lymphotrophic virus

BACKGROUND: The risk of transfusion transmitted viral infection is now so low that mathematical modelling is required to estimate the residual risk. The first national viral risk estimates for hepatitis B virus (HBV), human immunodeficiency virus (HIV) and hepatitis C virus (HCV) were recently published by the Australian Red Cross Blood Service. Using several refinements to the original methodology, as well as an additional 2 years of data, new risk estimates have been derived. METHODS: Viral screening data for Australian donors for 2000/2003 were retrospectively analysed. The data were applied to three published models to estimate the residual risk of transmitting HIV, HBV, HCV or human T lymphotrophic virus (HTLV) by blood transfusion in Australia. RESULTS: Applying the three models to HBV, HIV and HCV, three point estimates of the residual risk per unit were calculated for each virus. The median point estimates were 1 in 1,339,000 for HBV, 1 in 1 in 7,299,000 for HIV, and 1 in 3,636,000 for HCV. Although the HTLV risk could not be equivalently calculated because of the lack of incident infection it was estimated to be considerably less than 1 in 1,000,000 using a separate method. CONCLUSIONS: The most current and accurate estimate of residual risk of viral transmission in Australia has been provided in the present study. The residual risk in Australia is exceptionally small, continuing to decrease and is generally less than European or US risk estimates. These new estimates demonstrate that for viral transmission the Australian blood supply is amongst the safest in the world, and provide a basis for evaluating the cost benefit of future viral testing methodologies.     

Platelet transfusion therapy in acute leukemia: lack of effect of splenomegaly on transfusion requirements and risk of hemorrhage

Platelet transfusions are an important supportive measure during treatment for acute nonlymphocytic leukemia (ANLL). The presence of splenomegaly may produce decreased posttransfusion platelet increments leading some to recommend an increased dose of platelets per transfusion in this situation. Forty-nine newly diagnosed patients with ANLL were evaluated during 1980 and 1981, and 24% had palpable splenomegaly. Although treated with usual doses of platelets per transfusion, there was no detectable statistical increase in transfusion requirement or incidence of hemorrhage in patients with splenomegaly. Experimental evidence indicates that the splenic platelet pool enlarges with splenomegaly, but the life span of circulating platelets is not significantly changed. Furthermore, the splenic platelet pool is in dynamic equilibrium with the circulating platelet pool thus allowing these platelets to participate in hemostasis. Although posttransfusion increment in platelet count may be less, it appears that platelet transfusion therapy need not be altered solely because of splenomegaly.     

Estimation of the prevalence and rate of acute transfusion reactions occurring in Windhoek,Namibia

Background

Acute transfusion reactions are probably common in sub-Saharan Africa, but transfusion reaction surveillance systems have not been widely established. In 2008, the Blood Transfusion Service of Namibia implemented a national acute transfusion reaction surveillance system, but substantial under-reporting was suspected. We estimated the actual prevalence and rate of acute transfusion reactions occurring in Windhoek, Namibia.

Methods

The percentage of transfusion events resulting in a reported acute transfusion reaction was calculated. Actual percentage and rates of acute transfusion reactions per 1,000 transfused units were estimated by reviewing patients’ records from six hospitals, which transfuse >99% of all blood in Windhoek. Patients’ records for 1,162 transfusion events occurring between 1^st January – 31^st December 2011 were randomly selected. Clinical and demographic information were abstracted and Centers for Disease Control and Prevention National Healthcare Safety Network criteria were applied to categorize acute transfusion reactions¹.

Results

From January 1 – December 31, 2011, there were 3,697 transfusion events (involving 10,338 blood units) in the selected hospitals. Eight (0.2%) acute transfusion reactions were reported to the surveillance system. Of the 1,162 transfusion events selected, medical records for 785 transfusion events were analysed, and 28 acute transfusion reactions were detected, of which only one had also been reported to the surveillance system. An estimated 3.4% (95% confidence interval [CI]: 2.3–4.4) of transfusion events in Windhoek resulted in an acute transfusion reaction, with an estimated rate of 11.5 (95% CI: 7.6–14.5) acute transfusion reactions per 1,000 transfused units.

Conclusion

The estimated actual rate of acute transfusion reactions is higher than the rate reported to the national haemovigilance system. Improved surveillance and interventions to reduce transfusion-related morbidity and mortality are required in Namibia.     

Pathogen reduction and blood transfusion safety in Africa: strengths,limitations and challenges of implementation in low‐resource settings

Transfusion‐transmitted infection risk remains an enduring challenge to blood safety in Africa. A high background incidence and prevalence of the major transfusion‐transmitted infections (TTIs), dependence on high‐risk donors to meet demand, suboptimal testing and quality assurance collectively contribute to the increased risk. With few exceptions, donor testing is confined to serological evaluation of human immunodeficiency virus (HIV), hepatitis B and C (HBV and HCV) and syphilis. Barriers to implementation of broader molecular methods include cost, limited infrastructure and lack of technical expertise. Pathogen reduction (PR), a term used to describe a variety of methods (e.g. solvent detergent treatment or photochemical activation) that may be applied to blood following collection, offers the means to diminish the infectious potential of multiple pathogens simultaneously. This is effective against different classes of pathogen, including the major TTIs where laboratory screening is already implemented (e.g. HIV, HBV and HCV) as well pathogens that are widely endemic yet remain unaddressed (e.g. malaria, bacterial contamination). We sought to review the available and emerging PR techniques and their potential application to resource‐constrained parts of Africa, focusing on the advantages and disadvantages of such technologies. PR has been slow to be adopted even in high‐income countries, primarily given the high costs of use. Logistical considerations, particularly in low‐resourced parts of Africa, also raise concerns about practicality. Nonetheless, PR offers a rational, innovative strategy to contend with TTIs; technologies in development may well present a viable complement or even alternative to targeted screening in the future.     

医院输血科在输血质量管理中的实践探讨

<正>临床输血医学的迅速发展,给我们带来严峻的挑战!即如何保证输血质量,确保输血安全[1]。对拥有650张病床,年用血量6 000U的二等甲级综合医院的输血科来说,如何管理、提高输血质量是我们的工作重点。下面是我科近几年里实践探索和积累的部分经验,现报告如下。1积极开展创建活动,参加室间质评,提高输血质量2011年我院输血科申报了创建湖北省临床输血重点专科[2],参加了湖北省临检中心室间质量控制,从参加室间质控以来,每次质评(ABO正定型;     

输血科不合格标本的原因探析及改进

目的:探讨分析临床输血不合格标本产生的原因,保证临床用血安全。方法:选取2012年1―12月期间西安市红会医院输血科接收临床输血样本9 211例,对不合格标本进行原因分析,并指定出改进方案。结果:统计分析2012年上半年和下半年拒收例数分别为107例和24例,同比下降63.34%。样本不合格因素包括:申请单信息有误、血型填写错误、医师未签字、血样信息有误、血量不足、样本溶血、血样无标识。各指标下半年较上半年下降率分别为:28.25%、8.16%、4.58%、14.50%、2.29%、2.29%、4.01%。结论:严格执行输血前样本审核制度,保证临床输血安全有效。     

输血前不规则抗体筛查与临床安全输血

目的：回顾性分析本院输血患者血型不规则抗体的检出情况,探讨输血前不规则抗体筛查的重要性和高危科室。方法：微柱凝胶法和聚凝胺法对需要输血的2500例患者血清进行不规则抗体筛检。结果：2500例申请输血的患者不规则抗体总阳性率为1.0%;微柱凝胶检出的敏感度为100%,聚凝胺法敏感度为88.0%,2种方法的敏感度差异具有统计学意义（P〈0.05）。肝病科、肛肠科以及肾病科不规则抗体检出阳性率占了总阳性率的80.0%。结论：微柱凝胶法进行输血前不规则抗体的筛检敏感度高,更有利于保证临床上的输血安全;对于肝病科、肛肠科以及肾病科等出现反复输血的科室,在输血前更应该进行不规则抗体的筛查,以减少输血风险。     

Emerging pathogens and their implications for the blood supply and transfusion transmitted infections

The threat of infection by conventional transfusion‐transmitted agents has been essentially eliminated from the blood supply in developed countries, thus focusing attention on the potential risk from emerging infections. Over recent years, actions have been taken to manage a number of such risks to blood safety. These illustrate the inherent variability of the agents concerned and of the measures needed to define and control the risk.     

Screening for viral markers in volunteer and replacement blood donors in West Africa

BACKGROUND AND OBJECTIVES: West Africa is a highly endemic area for viral infections. The prevalence of five viral markers was determined in Ghanaian blood donors. MATERIALS AND METHODS: Replacement and volunteer blood donors were screened using enzyme immunoassays (EIAs) for hepatitis B surface antigen (HBsAg), human immunodeficiency virus antibodies (anti-HIV), HIV p24 antigen, human T-cell lymphocytotrophic virus-I and -II antibodies (anti-HTLV-I/II) and hepatitis C virus antibodies (anti-HCV). RESULTS: HBsAg was present at an equally high frequency (15%) in young volunteer (median age 18 years) and older replacement (median age 33 years) blood donors. In contrast, the prevalence of anti-HIV and anti-HCV was significantly higher in replacement blood donors (2.4 and 0.3%, respectively, P < 0.001). HCV RNA was detected in 74 or 55% of seropositive donors, depending on the confirmatory criteria used. No p24 antigen-positive/anti-HIV-negative donations were found. The prevalence of HTLV-I/II was generally low (0.5%). CONCLUSION: All blood donations should be screened for hepatitis B virus (HBV), HIV and HCV markers.     

New technology for transfusion safety

Hemovigilance programs from around the world document that the greatest risk to recipients of blood transfusion is human error, resulting in transfusion of the incorrect blood component. Errors in transfusion care have strong parallels with errors in medication administration. Errors often result from 'lapse' or 'slip' mistakes in which details of patient identification are overlooked. Three areas of transfusion are focal points for improved care: the labelling of the patient's pre-transfusion sample, the decision to transfuse and the final bedside check designed to prevent mis-transfusion. Both barcodes and radio-frequency identification technology, each ideally suited to matching alpha-numeric identifiers, are being implemented in order to improve performance sample labelling and the bedside check. The decision to transfuse should ultimately be enhanced through the use of nanotechnology sensors, computerised order entry and decision support systems. Obstacles to the deployment of new technology include resistance to change, confusion regarding the best technology, and uncertainty regarding the return-on-investment. By focusing on overall transfusion safety, deploying validated systems appropriate for both medication and blood administration, thoughtful integration of technology into bedside practice and demonstration of improved performance, the application of new technologies will improve care for patients in need of transfusion therapy.     

输血科在减少错误输血风险中的应对措施

<正>输血是一种宝贵且高危产品的静脉输注,要求准确性必须达到100%,且需符合多项法律法规和行规要求,因为输血工作的任何疏忽都可能以患者的生命为代价。临床输血前检验(患者ABO血型的正、反定型;不规则抗体筛查;输血相容性试验)的准确性尤为重要。输血科只有切实做好输血检验的质量控制,严格按照标准的检测方法、科学的思维方式、细致的工作态度做好输血前检验工作,方可减少错误输血的风险,本文就引起输血前试验     

关于将合理输血及疗效评估纳入输血科日常工作的设想

随着医院医疗卫生技术的发展,临床输血治疗已成为针对血细胞成分丢失病种的常规治疗手段。临床输血科不仅担任贮血、供血、配血等技术实施,还须进行临床用血的技术指导,     

Haematology patients and the risk of transfusion transmitted infection

A 2014 study by NHS Blood and Transplant indicated that over one quarter of red cells were transfused to patients with haematological conditions. For platelet components, the figure is higher. Certain diagnostic groups, such as haemoglobinopathies, myelodysplastic syndromes and some haemato‐oncology patients, receive multiple transfusion episodes, either over long periods, or more intensively over shorter periods. Haematology patients account for the majority of the multi‐transfused population. The risk of transfusion‐transmitted infection (TTI) increases with number of donor exposures, and the consequences of TTI are often more significant in immunosuppressed individuals. Historically, use of pooled plasma products in patients with clotting disorders resulted in widespread transmission of hepatitis B virus, hepatitis C virus and human immunodeficiency virus before effective screening and viral inactivation methods were introduced.     

Benefit and risk perceptions in transfusion medicine: blood and blood substitutes

Blood transfusion is a remarkably safe, routine procedure in clinical medicine. However, little attention has focused on the perceptions of risk associated with the receipt of blood, blood products or 'blood substitutes'. It is pertinent to ask (i) what key stakeholder groups know about transfusion, (ii) how safe they perceive blood/blood products to be, (iii) how the latter information might influence their own and others' perceptions of risk linked to transfusion, and (iv) the extent to which approved blood substitutes might be preferred over autologous or donor blood. An appreciation of what stakeholders perceive to be the benefits and risks of the receipt of blood and blood substitutes will inform future transfusion strategies. To obtain such information, a programme of research has been initiated at Nottingham. Surveys have targeted key stakeholder groups, namely, UK adult blood donors and nondonors, anaesthetists, general practitioners and health care journalists. Experimental studies examining message framing and cueing have also been conducted with undergraduate students. Such research will improve misunderstandings about current issues associated with blood donation and transfusion against the backdrop of changing public trust of health care professionals and attitudes and expectations on blood safety and benefits of blood substitutes.