To err is human … so how can we prevent all ABO-incompatible transfusions?
Abstract
Savin et al. report a retrospective analysis of ABO-incompatible red cell transfusions in the United Kingdom, France and Germany. In spite of varied strategies for bedside preventative measures, all three countries continue to identify preventable errors leading to ABO-incompatible red cell transfusions. This report highlights the ongoing challenge of human error as a factor in the persistence of preventable mistransfusions.
Commentary on: Savin et al. Frequencies and causes of ABO-incompatible red cell transfusions in France, Germany and the United Kingdom. Br J Haematol 2025; 206:726-734.
With Landsteiner's discovery of ABO blood group compatibility in 1900, safe human-to-human blood transfusion became possible.1 However, despite robust systems designed to ensure that patients receive ABO-compatible units, mistransfusion events persist, sometimes resulting in patient fatalities.2, 3 In 2000, Linden and colleagues reported that the rate of ABO-incompatible transfusions in New York state was 2.6/100 000 units administered.4 Errors leading to mistransfusion were found to occur at many steps in the complex ‘vein-to-vein’ process that begins with registering a blood donor and ends with transfusing a patient. In the Linden study, the most common cause of ABO-incompatible transfusion was incorrectly identifying the patient at the very end of the process, just as blood was about to be administered.4 While ABO-incompatible transfusions today are perhaps 10-fold less common than in 2000 (below), no one has devised a way to prevent them entirely. In the UK's 2023 Annual Serious Hazards of Transfusion (SHOT) report, for example, seven ABO-incompatible red cell transfusions were reported. There were no fatalities, but two cases resulted in major morbidity. All seven mistransfusions were attributed to sample collection errors (n = 4) or blood administration errors (n = 3) as opposed to laboratory errors.5
In their paper, Savin et al. provide a retrospective analysis of ABO-incompatible red cell transfusions in the United Kingdom, France and Germany between 2013 and 2022.6 The investigators sought to compare the efficacy of the bedside safety procedures used in each country to prevent ABO-incompatible transfusions. In the United Kingdom, use of a formal bedside checklist has been recommended since 2017, and electronic patient identification (ePPID) at the time of blood administration is increasingly being adopted to verify suitability between the patient and the component. In both France and Germany, a bedside ABO compatibility test is performed, primarily by nurses in France and by physicians in Germany.
Across the 10-year study period, there were 0.17/100 000 ABO-incompatible transfusions in the United Kingdom, 0.19/100 000 in France and 0.71/100 000 in Germany.6 These findings indicate that current measures to ensure safety at the time of component administration remain vulnerable to human error. In all three countries, most ABO-incompatible transfusions were attributed to administering a unit intended for another patient in the same or different clinical area (UK, 76%; France, 85%; and Germany, 51%). Germany also had a sizable number of errors due to choosing the wrong recipient at the time of issue (42%). In principle, these errors should have been caught by either the bedside compatibility test performed in Germany and France or the bedside checklist performed in the United Kingdom. However, these interventions remain vulnerable to human error. In all three countries, most of the ABO-incompatible transfusions were attributed to the safety intervention being incorrectly performed or incorrectly interpreted.
It seems intuitive that performing bedside ABO testing immediately before blood administration would eliminate the risk of an ABO-incompatible transfusion. Rarely, however, all required processes including bedside ABO testing are performed perfectly—and then the unit is hung on the wrong patient.7 Although both France and Germany utilize bedside ABO testing, in this study, the error rates were threefold higher in Germany. This difference may be an underestimate, as the authors acknowledge that ABO-incompatible transfusions in Germany may have been under-reported. In addition, the frequency of ABO-incompatible transfusion appears to be increasing in Germany since 2019. The different error rates observed may reflect differences in the test procedure (described in a national guideline in France and in institutional procedures in Germany) and/or in the staff performing the test (primarily nurses in France and physicians in Germany). While we may not fully understand the reasons behind the differences in error rates between France and Germany, this report suggests that the bedside ABO compatibility test may add little value to transfusion safety, at least when compared to the approach in the United Kingdom using a formal bedside checklist and partial implementation of ePPID. In addition, bedside testing is technically challenging, time-consuming and stressful, particularly during emergencies.
The Savin study highlights the ongoing need to implement robust processes in the transfusion chain to minimize human errors.6 One approach gaining traction is using ePPID, where patient identity is confirmed by scanning a barcode on the patient wristband that matches the patient to a barcode on the specimen label at the time of specimen collection or on the blood component at the time of transfusion. Using ePPID during specimen collection has been demonstrated to reduce wrong blood in tube (WBIT) errors.8 A WBIT is defined as a situation where the sample in the tube is from a different patient than the one indicated on the specimen label. These errors tend to occur more commonly in higher acuity areas such as the emergency department and inpatient wards versus outpatient clinics, suggesting that stress and time pressure may contribute to errors made at the time of specimen collection.9 Additional contributing factors include protocol violations, knowledge gaps and slips/lapses.10
Implementing ePPID reduces risk for ABO-incompatible transfusions. However, ePPID still requires humans to engage appropriately with the system and stringently follow all necessary protocols. As experience with ePPID systems increases, so too does our recognition of the numerous and unexpected ways these systems may fail. These include errors such as a patient wearing a wristband belonging to another patient or staff scanning wrist bands not affixed to patients.11 As Savin et al. appropriately acknowledge, there is ‘no single reliable, systemic safety measure that can prevent all ABO-[incompatible transfusions] … yet, further reducing the risk of ABO-[incompatible transfusion] must remain a transfusion safety priority’.6 Preventing 100% of ABO-incompatible transfusions may prove to be impossible. For the sake of our patients, however, we are obligated to try.