Managing change to improve transfusion safety

Comparative Analysis of Clinical Samples Showing Weak Serum Reaction on AutoVue System Causing ABO Blood Typing Discrepancies

Background

ABO blood typing in pre-transfusion testing is a major component of the high workload in blood banks that therefore requires automation. We often experienced discrepant results from an automated system, especially weak serum reactions. We evaluated the discrepant results by the reference manual method to confirm ABO blood typing.

Methods

In total, 13,113 blood samples were tested with the AutoVue system; all samples were run in parallel with the reference manual method according to the laboratory protocol.

Results

The AutoVue system confirmed ABO blood typing of 12,816 samples (97.7%), and these results were concordant with those of the manual method. The remaining 297 samples (2.3%) showed discrepant results in the AutoVue system and were confirmed by the manual method. The discrepant results involved weak serum reactions (<2+ reaction grade), extra serum reactions, samples from patients who had received stem cell transplants, ABO subgroups, and specific system error messages. Among the 98 samples showing ≤1+ reaction grade in the AutoVue system, 70 samples (71.4%) showed a normal serum reaction (≥2+ reaction grade) with the manual method, and 28 samples (28.6%) showed weak serum reaction in both methods.

Conclusions

ABO blood tying of 97.7% samples could be confirmed by the AutoVue system and a small proportion (2.3%) needed to be re-evaluated by the manual method. Samples with a 2+ reaction grade in serum typing do not need to be evaluated manually, while those with ≤1+ reaction grade do.

Tainted blood: Probing safety practices in the Danish blood system

The existing literature on donor screening in transfusion medicine tends to distinguish between social concerns about discrimination and medical concerns about safety. In this article, we argue that the bifurcation into social and medical concerns is problematic. We build our case on a qualitative study of the historical rise and current workings of safety practices in the Danish blood system. Here, we identify a strong focus on contamination in order to avoid ‘tainted blood’, at the expense of working with risks that could be avoided through enhanced blood monitoring practices. Of further significance to this focus are the social dynamics found at the heart of safety practices aimed at avoiding contamination. We argue that such dynamics need more attention, in order to achieve good health outcomes in transfusion medicine. Thus, we conclude that, to ensure continuously safe blood systems, we need to move beyond the bifurcation of the social and medical aspects of blood supply as two separate issues and approach social dynamics as key medical safety questions.

Bayesian evaluation of the human immunodeficiency virus antibody screening strategy of duplicate enzyme-linked immunosorbent assay in Xuzhou Blood Center, China

BACKGROUND

Accurate estimation of the risk of human immunodeficiency virus (HIV) infection through transfusion is essential for monitoring blood safety. The risk, however, is so low that it can only be estimated by mathematical modeling. With the Bayesian dependence model, this study evaluates the HIV antibody screening strategy of duplicate enzyme-linked immunosorbent assay (ELISA) in Xuzhou Blood Center and therefore estimates part of the total risks of transfusion-transmitted HIV infection.

STUDY DESIGN AND METHODS

Data from Xuzhou Blood Center between 2004 and 2008 were used. Information was obtained on donor profiles and screening and confirmatory test results. The portion of the risks of HIV infection through transfusion concerned was estimated by evaluating the screening algorithm in terms of its accuracy and predictive power with the Bayesian dependence model.

RESULTS

A total of 234,602 donations from voluntary blood donors in Xuzhou Blood Center were screened for HIV antibody. For the study screening algorithm, its sensitivity, specificity, false-positive predictive value (FPPV), and false-negative predictive value (FNPV) were 0.9951 (95% Bayesian credible interval [BCI], 0.9763-0.9997), 0.9991 (95% BCI, 0.9990-0.9992), 0.9647 (95% BCI, 0.9018-0.9923), and 1.52 × 10(-7) (95% BCI, 7.31 × 10(-9) -1.15 × 10(-6) ), respectively. For the positive detection rate (9.60 × 10(-4) ) and FPPV (0.9647), the differences between their own Bayesian median estimates and real values were 2.70 × 10(-5) and -0.0033, respectively.

CONCLUSIONS

The HIV antibody screening algorithm of duplicate ELISA is well evaluated in its accuracy and predictive power with the Bayesian dependence model. The FNPV measures the part of the risks of transfusion-associated HIV transmission concerned.

Motivators and barriers to blood donation in African American college students

BACKGROUND

An adequate blood supply depends on volunteer non-remunerated blood donors. African Americans have lower blood donation rates than whites. To improve African American blood donation rates, the motivators and barriers to African Americans must be explored. This study investigated the differences in motivators and barriers to blood donation between donor and non-donor African American college students.

METHODS

African Americans college students at two Historically Black Colleges and Universities completed a 41-item, self-administered questionnaire, which assessed participant's donation frequency, motivators and barriers toward donation, and knowledge and beliefs towards blood donation.

RESULTS

Three hundred and sixty four primarily female college students (96% African Americans, 93% female) completed the questionnaire. Forty-nine percent reported prior blood donation experience (donors) and 51% were non-donors. The primary motivator for donors and non-donors was convenience (89% donor, 82% non-donor). Donors were more likely than non-donors to disagree with statements regarding blood donation as being too painful (82% donor, 44% non-donor), resulting in feeling faint, dizzy, or nauseated (61% donor, 29% non-donor). Donors more often agreed that the blood supply is safe (77% donor, 58% non-donor), less often concerned about receiving a transfusion (61% donor, 73% non-donor), and more often aware of local blood shortages (50% donor, 35% non-donor).

CONCLUSIONS

African Americans female college students are willing to donate blood given convenience and support from their university. Educational campaigns to increase knowledge regarding the safety of the blood donation process and the ongoing needs of an adequate blood supply might be effective methods to increase blood donation.

Can intravenous iron therapy meet the unmet needs created by the new restrictions on erythropoietic stimulating agents?

In 2008, after reports of an association between erythropoietic stimulating agent (ESA) therapy and the potential for either thrombotic cardiovascular events or more rapid tumor progression in some cancers, the Food and Drug Administration changed the product labeling for ESAs, adding a black box warning as well as more restrictive indications, especially in oncology patients. In addition the Centers for Medicare and Medicaid Services has placed significant restrictions on payments for ESA therapy. These new limitations on ESA have led to increased use of transfusions in anemic cancer patients. This increase in allogeneic transfusions potentially will place an additional burden on the US blood supply. Although allogeneic blood transfusion is one answer to ESA restrictions, the use of intravenous iron therapy (IV iron) is another possible alternative. We will discuss the use of IV iron as primary therapy for anemia, the use of combination IV iron and ESA therapy to improve efficiency and decrease costs, and evidence that IV iron with and without ESA therapy can reduce allogeneic blood transfusions in surgical patients. We will also review the available IV iron agents and their comparative safety profiles.

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.

Consenting to blood: what do patients remember?

We sought to characterize the consent process for transfusion and determine its impact on patients' knowledge and level of comfort with receiving blood. We identified all adult patients who had received blood transfusion at a tertiary care centre over 3 months. Patients who were discharged each received a survey that assessed their (1) recall of the consent process, (2) recall of information conveyed, (3) assessment of the discussion's understandability and (4) perceived knowledge of as well as comfort level with transfusion as a result of the discussion. Overall, 80% of respondents recalled discussing and signing an informed consent. Information was mostly conveyed by attending physicians (35%) and consent obtained in the patient's hospital room (38%) or the preadmission clinic (19%). Although the majority recalled the consent process, many did not recall the discussion of specific transfusion risks or alternatives to donor blood (88%). Although the majority felt the discussion was at least somewhat understandable (77%), only 35% felt better informed and more comfortable with accepting blood. Despite implementation of written informed consent for transfusion, patients' recollection and understanding of risks and alternatives remain poor. This suggests the need for improving risk communication.

Evaluation of the enhanced bacterial detection system for screening of contaminated platelets

BACKGROUND

The Pall third-generation enhanced bacterial detection system (eBDS) was recently approved for detection of bacterial contamination in leukoreduced platelets (PLTs). The method is based on the measurement of the oxygen content as a marker for bacteria. eBDS incorporates major modifications including removal of the sample-set filter, modification of the culture medium, and incubation with agitation of the sample pouch.

STUDY DESIGN AND METHODS

Ten whole blood-derived random-donor PLT units collected on Day 1 after donation and 10 single-donor apheresis PLT units were spiked with low levels of bacteria in three different blood transfusion centers. Inoculation was performed at a final concentration of 5 to 50 colony-forming units per mL with reference strains of five organisms involved in severe transfusion-associated infections. PLT units were stored at 22 degrees C for 24 hours before sampling. Six sample sets were then sterile-connected to each unit and placed on a horizontal agitator at 35 degrees C for 18 or 24 hours of incubation.

RESULTS

No false-positive results were obtained, indicating a 100 percent specificity of the assay. Of 126 spiked sample pouches tested, 61 of 63 (96.82%) and 63 of 63 (100%) were detected positive after 18 or 24 hours of incubation, respectively. In the two missed cases that failed to detect Bacillus cereus, the measured oxygen was slightly above the detection threshold but was markedly different from the negative samples.

CONCLUSION

The eBDS method allows definitive testing of PLTs as soon as 42 hours after collection and offers an alternative culture method to the BacT/ALERT system.

Residual risk of transfusion-transmitted human immunodeficiency virus, hepatitis C virus, and hepatitis B virus infections in Italy

BACKGROUND

Estimating the risk of transfusion-transmitted infections (TTIs) is essential for monitoring blood safety. The residual risk of TTI was estimated for nearly 90 percent of the blood supply in Italy.

STUDY DESIGN AND METHODS

Data were analyzed from 1,079,281 repeat donors, corresponding to 5,361,000 donations made in blood transfusion centers throughout Italy in the period 1999 through 2001. The residual risk of transfusion-transmitted human immunodeficiency virus (HIV), hepatitis C virus (HCV), and hepatitis B virus (HBV) infections was estimated with the incidence rate-window period model. The denominator for the incidence rate (i.e., the number of person-years at risk) was estimated on a sample of 5850 donors.

RESULTS

The risk of an infectious donation entering the blood supply, per 1 million donations, was 1.91 (probable range, 0.52-3.32) for HIV, 16.74 (9.57-24.01) for HCV, and 69.16 (43.12-102.70) for total HBV (adjusted for vaccination and hepatitis B surface antigen transience).

CONCLUSION

In Italy, the estimated residual risk of TTI is apparently low, particularly for HIV infection. Although the estimated risks are higher for HCV and HBV, the introduction of mandatory viral detection tests for HCV in 2002 should account for an 80 percent reduction in the HCV risk. Moreover, the ongoing HBV vaccination program will contribute to reducing the risk of transfusion-transmitted HBV.

Reengineering transfusion and cellular therapy processes hospitalwide: ensuring the safe utilization of blood products

Efforts to make blood transfusion as safe as possible have focused on making the blood in the bag as disease-free as possible. The results have been dramatic, and the costs have been correspondingly high. Although blood services will have to continue to deal with emerging pathogens, efforts to reduce the transfusion of infectious agents presently posing a risk will require high incremental costs and result in only improvements of a small magnitude. The other aspect of safe blood transfusion, the actual transfusion process performed primarily in hospitals, has been accorded considerably less interest. We should turn our attention to enhancing overall blood safety by focusing on improving the process of blood transfusion. Errors involving patient, specimen, and blood product identification put transfused patients at risk, increasing the mortality risk for some. Solutions that could improve the transfusion process are discussed as a focus of this article.