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Background and Objectives: Donor characteristics have been implicated in transfusion‐related adverse events. Uncertainty remains about whether sex, and specifically pregnancy history of the blood donor, could affect patient outcomes. Whether storage duration of the blood product could be important for patient outcomes has also been investigated, and a small detrimental effect of fresh products remains a possibility. Here, we hypothesize that fresh red blood cell products donated by ever‐pregnant donors are associated with mortality in male patients. Materials and Methods: We used data from a cohort study of adult patients receiving a first transfusion between 2005 and 2015 in the Netherlands. The risk of death after receiving a transfusion from one of five exposure categories (female never‐pregnant stored ≤10 days, female never‐pregnant stored >10 days, female ever‐pregnant stored ≤10 days, female ever‐pregnant stored >10 days and male stored for ≤10 days), compared to receiving a unit donated by a male donor, which was stored for >10 days (reference), was calculated using a Cox proportional hazards model. Results: The study included 42,456 patients who contributed 88,538 person‐years in total, of whom 13,948 died during the follow‐up of the study (33%). Fresh units (stored for ≤10 days) from ever‐pregnant donors were associated with mortality in male patients, but the association was not statistically significant (hazard ratio 1.39, 95% confidence interval 0.97–1.99). Sensitivity analyses did not corroborate this finding. Conclusion: These findings do not consistently support the notion that the observed association between ever‐pregnant donor units and mortality is mediated by blood product storage. [ABSTRACT FROM AUTHOR]

Purpose: Apixaban is a factor Xa inhibitor used in patients undergoing hemodialysis treatment. The objective of this study is to investigate the effect of hemodialysis on apixaban plasma concentrations. Methods: This observational study is on patients treated with apixaban 2.5 mg twice daily on conventional hemodialysis with standard low‐molecular‐weight heparin (LMWH) anticoagulation (nadroparin 3800–7600 IU). Plasma blood samples were collected before starting dialysis (t1), 2 h after starting dialysis (t2), and directly after dialysis (t3). Apixaban concentration was measured before and after dialysis. Anti‐Xa activity was measured for all three samples. Results: A significant difference was observed between the apixaban concentration before and after dialysis (mean before dialysis 141.03 ng/mL; mean after dialysis 102.71 ng/mL; p = 0.003). Nonetheless, both apixaban plasma concentrations and anti‐Xa levels remained within the reference range. Anti‐Xa levels had a strong correlation with the apixaban concentrations (r = 0.935, p = 0.000). Thus, anti‐Xa activity might be used as a surrogate for apixaban plasma concentration. Conclusion: There seems to be no need for dose adjustments of apixaban; co‐administration of LMWH next to apixaban might also be unnecessary. [ABSTRACT FROM AUTHOR]

Background: Both one‐stage (OSA) and chromogenic substrate assays (CSA) are used to measure factor VIII (FVIII) activity. Factors explaining analytical variation in FVIII activity levels are still to be completely elucidated. Aim: The aim of this study was to investigate and quantify the analytical variation in OSA and CSA. Methods: Factors determining analytical variation were studied in sixteen lyophilized plasma samples (FVIII activity <0.01‐1.94 IU/mL) and distributed by the ECAT surveys. To elucidate the causes of OSA variation, we exchanged deficient plasma between three company set‐ups. Results: On average, 206 (range 164‐230) laboratories used the OSA to measure FVIII activity and 30 (range 12‐51) used CSA. The coefficient of variation of OSA and CSA increased with lower FVIII levels (FVIII <0.05 IU/mL). This resulted in misclassification of a severe haemophilia A sample into a moderate or mild haemophilia A sample in 4/30 (13.3%) of CSA measurements, while this was 37/139 (26.6%) for OSA. OSA measurements performed with reagents and equipment from Werfen showed slightly lower FVIII activity (0.93, IQR 0.88‐0.98 IU/mL) compared to measurements with Stago (1.07, IQR 1.02‐1.14 IU/mL) and Siemens (1.03, IQR 0.97‐1.07 IU/mL). Part of this difference is explained by the value of the calibrator. For CSA, the measured FVIII levels were similar using the different kits. Conclusions: In the lower range (<0.05 IU/mL), analytical variation of FVIII measurements is high in both OSA and CSA measurements. The variation in FVIII activity levels was partly explained by specific manufacturers. Further standardization of FVIII measurements and understanding of analytical variation is required. [ABSTRACT FROM AUTHOR]

Background Phlebotomy for the purpose of blood analysis is often performed at remote locations, and samples are usually temporarily stored before transport to a central laboratory for analysis. The circumstances during storage and shipment may not meet the necessary requirements. If analysed anyway, false results may be generated. We therefore examined the influence of precentrifugation time and temperature of the most frequently requested tests in whole blood. Methods Healthy volunteers donated blood in which 48 analytes were tested. Routine chemistry was performed in lithium heparin tubes, haematology in ethylenediaminetetraacetic acid tubes, coagulation in citrate tubes and glucose in sodium fluoride tubes. One tube was measured directly. The others were kept at different temperatures (4, 8, 20 or 30℃) and stored for 4, 6, 8 or 24 h before analysis. Additionally, some analytes were examined at 12, 16, 24 and 28℃. The mean percentage deviation was compared with different decision levels, including the total allowable error. Results When using the total allowable error as an acceptable limit, most of the investigated analytes remained stable. However, bicarbonate is unstable at almost all tested time-points and temperatures. Calcium, lactate dehydrogenase, potassium and sodium are particularly affected at low temperatures, while phosphate is mainly affected at and above room temperature after 8 h. Conclusion We established the influence of time and temperature on a broad range of analytes, which may be applied to set the limits in transportation and storage of whole blood samples. [ABSTRACT FROM AUTHOR]

Previous studies found exposure to red blood cell transfusions from female donors who have been pregnant reduces survival in male patients compared to exposure to male donor products, but evidence is not consistent. We postulate the previously observed association is modified by offspring sex, with an expected increased mortality risk for male patients receiving units from female donors with sons. Here, marginal structural models were used to assess the association between exposure to units from ever-pregnant donors, ever-pregnant donors with sons and ever-pregnant donors with daughters, and mortality. Clinical data were collected on first-ever transfusion recipients in the Netherlands and donor data were supplemented with information about offspring sex and date of birth. In this analysis, 56,825 patients were included, of whom 8,288 died during follow-up. Exposure to red blood cell units from ever-pregnant donors with sons was not associated with increased all-cause mortality risk among male transfusion recipients (hazard ratio [HR]=0.91, 95% confidence interval [CI]: 0.83-1.01). Exposure to ever-pregnant donors, irrespective of offspring sex, was associated with mortality in male patients aged between 18 and 50 years (ever-pregnant donors: HR=1.81, 95% CI: 1.31-2.51) compared to male donor units, but was protective in female patients. This study suggests that the observed increased mortality risk for exposure to red blood cell units from parous female donors does not depend on offspring sex. The increased risk of mortality seen in younger adult male patients is consistent with previous observations, but the underlying biological mechanism could not be identified in this study.

Introduction: The high incidence of thrombotic events in patients with COVID-19 affects health care worldwide and results in an increased workload in haemostasis laboratories due to more frequent testing of D-dimer, haemostatic parameters and anti-Xa tests. However, the impact of this increase in assay requests on the quality of performance in haemostasis laboratories remains unclear. In this study, the impact of the COVID-19 pandemic on the quality of performance and management of haemostasis laboratories was evaluated., Methods: The impact on the quality of performance was studied using external quality assessment data from 2019 to 2020 derived from ECAT surveys. A questionnaire was sent to Dutch haemostasis laboratories to identify challenges and management strategies. Furthermore, the number of assays performed in 2019 and 2020 was supplied by four Dutch hospitals, located in regions with different disease incidence., Results: No differences in response rate nor the quality of the measurements were observed between the EQA surveys in 2019 and 2020. The questionnaire results showed a large increase of >25% in the number of test requests for anti-Xa, D-dimer and fibrinogen assays in 2020 compared to 2019. Extreme peaks in test requests were also observed in the four evaluated hospitals. Additionally, 84% of the respondents indicated that they had experienced increased work pressure, and increased sick leave was observed in 71% of the participating laboratories., Conclusions: The enormous increase in test requests, especially for D-dimer assays and anti-Xa activity, did not affect the quality of performance within haemostatic laboratories during the COVID-19 pandemic., (© 2021 John Wiley & Sons Ltd.)

Background: Renal failure and renal replacement therapy (RRT) affect the immune system and could therefore modulate red blood cell (RBC) alloimmunization after transfusion., Study Design and Methods: We performed a nationwide multicenter case-control study within a source population of newly transfused patients between 2005 and 2015. Using conditional multivariate logistic regression, we compared first-time transfusion-induced RBC alloantibody formers (N = 505) with two nonalloimmunized recipients with similar transfusion burden (N = 1010)., Results: Renal failure was observed in 17% of the control and 13% of the case patients. A total of 41% of the control patients and 34% of case patients underwent acute RRT. Renal failure without RRT was associated with lower alloimmunization risks after blood transfusion (moderate renal failure: adjusted relative rate [RR], 0.82 [95% confidence interval (CI), 0.67-1.01]); severe renal failure, adjusted RR, 0.76 [95% CI, 0.55-1.05]). With severe renal failure patients mainly receiving RRT, the lowest alloimmunization risk was found in particularly these patients [adjusted RR 0.48 (95% CI 0.39-0.58)]. This was similar for patients receiving RRT for acute or chronic renal failure (adjusted RR, 0.59 [95% CI, 0.46-0.75]); and adjusted RR, 0.62 [95% CI 0.45-0.88], respectively)., Conclusion: These findings are indicative of a weakened humoral response in acute as well as chronic renal failure, which appeared to be most pronounced when treated with RRT. Future research should focus on how renal failure and RRT mechanistically modulate RBC alloimmunization., (© 2020 The Authors. Transfusion published by Wiley Periodicals LLC. on behalf of AABB.)

Red cell alloimmunization may induce severe hemolytic side effects. Identification of risk-modifying conditions will help tailor preventative strategies. This study aims to quantify the associations of hematologic malignancies and solid cancers with red cell alloimmunization in patients receiving red cell transfusions. We performed a nested multicenter case-control study in a source population of 24,063 patients receiving their first and subsequent red cell transfusions during an 8-year follow-up period. Cases (n=505), defined as patients developing a first transfusion-induced red cell alloantibody, were each compared with 2 non-alloimmunized controls (n=1010) who received a similar number of red cell units. Using multivariate logistic regression analyses, we evaluated the association of various malignancies and treatment regimens with alloimmunization during a delineated 5-week risk period. The incidence of alloimmunization among patients with acute (myeloid or lymphoid) leukemia and mature (B- or T-cell) lymphoma was significantly reduced compared to patients without these malignancies: adjusted relative risks (RR) with 95% confidence interval (CI) 0.36 (range 0.19-0.68) and 0.30 (range 0.12-0.81). Associations were primarily explained by immunosuppressive treatments [RR for (any type of) chemotherapy combined with immunotherapy 0.27 (95%CI: 0.09-0.83)]. Alloimmunization risks were similarly diminished in allogeneic or autologous stem cell transplanted patients (RR 0.34, 95%CI: 0.16-0.74), at least during the six months post transplant. Alloimmunization risks of patients with other hematologic diseases or solid cancers, and their associated treatment regimens were similar to risks in the general transfused population. Our findings suggest that, in contrast to malignancies in general, hemato-oncological patients treated with dose-intensive regimens have strongly diminished risk of red cell alloimmunization., (Copyright© Ferrata Storti Foundation.)