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Background: Fetal and neonatal exposure to lead is associated with irreversible adverse effects on neural development. There is no reliable threshold for lead effect, so limiting exposure is recommended. A significant correlation has been reported between post‐transfusion blood lead level (BLL) in infants and lead levels in transfused RBC units. We measured levels of lead, mercury, and cadmium, in Canadian donor blood to investigate if concerning levels for neonatal transfusion exist. Study Design and Methods: Whole blood samples from blood donors (n = 2529) were shipped cold within 7 days of donation. All permanent blood donation clinics across Canada were sampled. Twelve of these permanent clinics and 8 mobile clinics with a greater potential for having higher lead or mercury levels were oversampled. Heavy metals were measured by inductively coupled plasma mass spectrometry. Results: Of all donations, 2.2% (lead) and 0.4% (mercury) had levels higher than the recommended thresholds for safe neonatal transfusion. BLLs were higher in males but there was no significant difference in the blood mercury levels of males versus females. Cadmium levels were higher in females. There was a positive correlation between donor age and levels of heavy metals, with lead having the strongest correlation (r = 0.47, p <.0001). Three clinics in close proximity to two lead‐producing mines were among the clinics with the highest BLLs. Significantly higher blood mercury levels were observed in coastal clinics. Conclusion: Our data on donor blood heavy metal levels supports considering blood transfusion as an exposure source to heavy metals and encourages informed selection of blood units for transfusion to vulnerable groups. [ABSTRACT FROM AUTHOR]

Background: Case detection underestimates the burden of the COVID-19 pandemic. Following the first COVID-19 wave, we estimated the seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among blood donors across Canada.Study Design and Methods: This serial cross-sectional study was conducted between May 9 and July 21, 2020 from blood donors donating at all Canadian Blood Services locations. We used the Abbott Architect assay to detect SARS-CoV-2 IgG antibodies from retention plasma. Seroprevalence was standardized to population-level demographics and assay characteristics were adjusted using the Rogan-Gladen equation. Results were stratified by region, age, ethnicity, ABO groups, and quantiles of material and social deprivation indices. Temporal trends were evaluated at 2-week intervals. Univariate and multivariate logistic regression compared SARS-CoV-2 reactive to non-reactive donors by sociodemographic variables.Results: Overall 552/74642 donors, had detectable antibodies, adjusted seroprevalence was 7.0/1000 donors (95% CI; 6.3, 7.6). Prevalence was differential by geography, Ontario had the highest rate, 8.8/1000 donors (7.8, 9.8), compared to the Atlantic region 4.5/1000 donors (2.6, 6.4); adjusted odds ratio (aOR) 2.2 (1.5, 3.3). Donors that self-identified as an ethnic minority were more likely than white donors to be sero-reactive aOR 1.5 (1.2, 1.9). No temporal trends were observed.Discussion: Worldwide, blood services have leveraged their operational capacity to inform public health. While >99% of Canadians did not show humoral evidence of past infection, we found regional variability and disparities by ethnicity. Seroprevalence studies will continue to play a pivotal role in evaluating public health policies by identifying trends and monitor disparities. [ABSTRACT FROM AUTHOR]

Background: At Canadian Blood Services, platelet concentrate (PC) shelf life was extended to 7 days with a large-volume, delayed-sampling bacterial screening algorithm. We present the development study and postimplementation results.Study Design and Methods: In the development study, PCs inoculated with five bacteria (various concentrations) were incubated for 7 days with daily sampling for BacT/ALERT cultures and bacterial quantification. After implementation, from August 2017 to December 2019, a total of 223 156 pools and 39 725 apheresis units and 5310 outdated PCs were screened. Since March 2018, cocomponents associated to false-positive results have been released to inventory.Results: In the development study, Klebsiella pneumoniae, Serratia marcescens, and Staphylococcus aureus were detected at concentrations of at least 0.01 colony-forming units (CFUs)/mL at 24 hours postinoculation. However, Staphylococcus epidermidis was detected at concentrations of less than 0.16 CFUs/mL only more than 48 hours postinoculation. After implementation, 776 (0.35%) and 303 (0.77%) initial-positive results and 201 (0.09%) and 16 (0.04%) confirmed-positive results were obtained for pools and apheresis units, respectively, predominantly with Cutibacterium acnes. Other organisms included staphylococci, streptococci, Klebsiella oxytoca and Pseudomonas aeruginosa. One nonfatal reaction involving a 7-day pool contaminated with S. epidermidis occurred. Approximately, 1-in-1000 false-negative screening results were obtained during testing of outdated PCs. Approximately 1000 cocomponents associated with false-positive results were released into inventory. Combined PC outdating at Canadian Blood Services and hospitals was reduced from 18.9% to 13.1%.Conclusion: Screening of 7-day PCs increased bacterial detection mainly of anaerobes and reduced outdating. The incidence of septic transfusion events has decreased approximately threefold. A longer surveillance period is needed to evaluate the value of anaerobic cultures and residual safety risk. [ABSTRACT FROM AUTHOR]

Background: In Canada, the deferral for men who have sex with men (MSM) has been progressively reduced from a permanent deferral for MSM since 1977, to 5 years, 1 year, and, most recently, 3 months. We estimated human immunodeficiency virus (HIV) residual risk and compliance with the MSM time deferral after each change. Methods: Four anonymous online compliance surveys were carried out before and after each change. HIV incidence and prevalence were monitored from 2010 to 2021. Residual risk was estimated using the incidence‐window period model. Results: Human immunodeficiency virus prevalence, incidence, and residual risk did not change with incrementally shorter MSM deferrals. The residual risk per million donations post 3‐month deferral was 0.05 (0.001–0.371). Men with temporally remote MSM history became eligible and, therefore, compliant as the deferral periods decreased (Cochran‐Armitage p value = <.0001). However, the percentage of men with MSM history in the last 3 months with the indefinite deferral in place was similar to the percentage noncompliant, while the 3‐month deferral was in place. MSM donors did not report high‐risk behaviors for which they would otherwise be deferred in any survey. Following the change, an estimated 4467 MSM per year were eligible to donate, an increase from 2501 estimated eligible MSM donors following the change to the 1‐year deferral. Conclusion: With progressively shorter MSM deferral periods, HIV residual risk was unchanged. The proportion of male donors with deferrable MSM history remained low, while those with temporally remote MSM history became eligible, increasing the number of eligible MSM donors. [ABSTRACT FROM AUTHOR]

Background: This pilot study assesses the ability of plasma collected from Canadian blood donors in the first wave of the SARS‐CoV‐2 pandemic to neutralize later SARS‐CoV‐2 variants of concern (VOCs). Study design and methods: A repeated cross‐sectional design was used, and a random cross‐sectional sample of all available Canadian Blood Services retention samples (n = 1500/month) was drawn monthly for April and May of 2020. Qualitative IgG analysis was performed on aliquots of specimens using anti‐spike, anti‐receptor binding domain, and anti‐nucleocapsid protein enzyme‐linked immunosorbent assays as well as the Abbott Architect SARS CoV‐2 IgG assay (Abbott Laboratories) against the anti‐nucleocapsid protein. Selected plasma specimens were then assessed for neutralization against VOCs using pseudotyped lentivirus inhibition assays as well as plaque reduction neutralization test 50% (PRNT50). Results: Six specimens with a high neutralizing titer against wild‐type SARS‐CoV‐2 and three specimens with a low neutralizing titer against wild‐type SARS‐CoV‐2 were chosen for further analysis against VOCs. Four of six high neutralizing titer specimens had a reduced neutralizing capacity against beta VOCs by both neutralization methods. Three of six high neutralizing titer specimens had reduced neutralization capacity against gamma VOCs. Conclusions: This preliminary data can be used as a justification for limiting the use of first wave plasma products in upcoming clinical trials but cannot be used to speculate on general trends in the immunity of Canadian blood donors to SARS‐CoV‐2. [ABSTRACT FROM AUTHOR]

Background: We assessed donor return rates, donation frequency, and factors related to the evolution of ferritin levels 2 years after entering donors into a large operational study of ferritin testing.Study Design and Methods: Ferritin testing was done on donors from representative clinics (n = 12,595). Low-ferritin donors (<25 μg/L) were informed and not called for 6 months to book a donation. Approximately 37% of donors had ferritin retested on a return donation. Return rate and donation frequency were monitored, and a logistic regression model was constructed.Results: The return rate was lower in low-ferritin donors (67% vs. 78%), particularly in women who were first-time donors (36% vs. 61%). Returning low-ferritin donors made fewer donations in the 2 years after notification compared to the 2 years prenotification (4.5 vs. 7.5 for men, 3.0 vs. 5.0 for women), while donation frequency was lower and increased slightly for normal-ferritin donors (4.7 vs. 4.4 for men, 3.6 vs. 3.1 for women). An increased number of donations, shorter interdonation intervals, female sex, and younger age are associated with low ferritin levels on initial and repeat testing. Some recovery of ferritin occurred, but most low-ferritin donors continued to have low or borderline levels on retesting.Conclusion: Informing donors of low ferritin results had a long-lasting impact on return rates and donation frequency, requiring recruitment efforts to maintain adequacy of supply. Increasing the interdonation interval leads to some improvement in ferritin levels; more sustained efforts to encourage donors to improve iron intake are needed to achieve long-term benefit. [ABSTRACT FROM AUTHOR]

Background: Greater use of unrelated donors to support hematopoietic cell transplantation can be hampered by unavailability of registrants when identified as potential candidates for donation. Methods: Multivariate analysis was performed to identify donor factors associated with availability for verification of human leukocyte antigen typing (VT) needed before donor activation. All VT requests for registrants on the Canadian Blood Services Stem Cell Registry between 1 January and 31 December 2018 were reviewed (n = 1358). Results: Potential donors identified by transplant centers were categorized as available at the time of VT but ineligible for medical or other reasons (n = 130 and excluded from further analysis), available (n = 622) or unavailable (n = 566) due to scheduling, loss of interest, and/or inability to contact. With multivariate analysis, registrants who previously donated blood, those recruited online or from blood donation clinics, and a shorter interval between registration and VT request were significantly correlated with increased donor availability. Donor sex and geographic location, however, displayed no correlation. Conclusion: Online registration and recruitment at whole blood donation centers should be enhanced to increase the availability of registrants at VT. More insight is needed to maintain registrant availability following community in‐person recruitment events, especially if the interval between registration and activation is prolonged. Recruitment of male registrants who are well informed should not negatively impact availability. [ABSTRACT FROM AUTHOR]

Background: Transfusion medicine standards in Canada state that adult recipients can be transfused with cryoprecipitate of any ABO group, however, not all hospitals follow this guideline. There is a paucity of data on cryoprecipitate anti‐A/B levels to reinforce standards. Study Design and Methods: Manual tube antibody titration was performed on 7 units of group O plasma and the corresponding cryosupernatant plasma and cryoprecipitate. IgG/IgM levels were determined by nephelometry. Additionally, 10 cryoprecipitate each from groups A, B, and O were similarly assessed. From the antibody titer distribution among these samples, the probability of making a pool of cryoprecipitate with a titer ≥1:100 was calculated using bootstrap analysis. Results: Anti‐A/B titers in cryoprecipitate were equivalent to those in corresponding plasma; partitioning of anti‐A/B activity into cryoprecipitate was not observed. Average IgM concentration was higher in cryoprecipitate than in plasma (P <.01). However, no correlation between IgM levels and anti‐A/B titers was established. Among 30 cryoprecipitates from routine blood bank inventory, the median antibody titer and mode were 1:32 and 1:16, respectively. Of the samples tested, 4 of 30 and 9 of 30 had titers above 1:100 and 1:50, respectively. The probability of transfusing an adult dose of cryoprecipitate (pool of 10 cryoprecipitate) with a titer higher than 1:100 was calculated to be less than 1 in 3 million. Conclusions: This study provides strong evidence to support current Canadian transfusion medicine standards on the safety of transfusion of cryoprecipitate without the need for blood group matching in adult recipients. See editorial on page 1–4, in this issue [ABSTRACT FROM AUTHOR]

Background: There are few studies investigating the effect of irradiation on red blood cells (RBCs) during storage. This study analyzed changes in in vitro quality of RBCs irradiated at several points during storage with the aim of providing evidence to support current maximum pre- and postirradiation storage limits.Study Design and Methods: Each of seven participating centers produced four pools of 7 standard RBC units (SAGM, AS-3, or PAGGSM), which were then split back into 7 units. All units in a pool were from sex-matched blood donors. Every week during 6 weeks of refrigerated storage, 1 unit was irradiated, while 1 unit was not irradiated (control). Units were tested weekly for biochemical variables, morphology, and mechanical fragility.Results: The earlier during storage that units were irradiated, the higher the hemolysis and K+ at end of storage. Irrespective of the timing of irradiation, there was a rapid increase in extracellular K+ , followed by a more gradual increase in hemolysis. ATP levels decreased faster in irradiated units and were reduced below accepted values if irradiated early. Irradiated female RBCs had an absolute lower hemolysis and K+ level compared to male RBCs at all time points.Conclusions: The method of blood component manufacturing determined the absolute levels of hemolysis and potassium in irradiated and nonirradiated units, but did not influence the effect that timing of irradiation had on the in vitro quality characteristics. This study provides support for the current Council of Europe guidelines on the time limitations for the irradiation of RBCs. [ABSTRACT FROM AUTHOR]