Low Hemoglobin Deferral Research Articles

Characteristics of first-time blood donors with unsatisfactory hemoglobin level and positive hepatitis B test in Binh Dinh Province

Blood transfusion is essential in the treatment of a various diseases. In order to guarantee a safe and sufficient volume of blood supply, it is crucial to select appropriate donors based on stringent eligibility criteria. The objective of this study was to furnish robust epidemiological information and identify the risk factors linked to hepatitis B virus (HBV) infection and low hemoglobin levels in first-time blood donors in Binh Dinh. Understanding the causes for donor deferrals can assist better plan and establish an efficient recruiting strategies as well as evaluate donor selection criteria. A cross-sectional study was undertaken in Binh Dinh Provincial General Hospital from November 2022 to February 2023 to examine individuals in their first-time blood donation. Data were sourced directly from voluntary blood donation registration forms. HBsAg results were assessed using rapid immunochromatographic tests and chemiluminescent immunoassays. The rate of unsatisfactory hemoglobin levels was 2.56% tested on 1,638 participants. This rate was significantly associated with female sex (18 times greater odds than males), and lower weight. The results revealed that the rate of HBV infection was 3.13% when detected by the rapid test, but increased by 0.58% when measured by chemiluminescent microparticle immunoassay. The positive hepatitis B deferral correlated with sex (p<0.05), age group (p<0.05) and occupation (p<0.05). HBV was found the leading cause of deferral in the study area and associated with males, age groups (25–35 and 36–44), officer, worker-farmer, and self-employed people. The prevalence of low hemoglobin donor deferral obtained was 2.56%. Low hemoglobin deferral is associated with female gender, lower body weight, worker-farmer, and self-employed - others. This finding underscores a significant public health concerns, highlighting the need for strategies to lower the infection rates. Understanding the factors leading to defered donation can contribute to development of proactive strategies for recruiting and retaining donors.

The risks of low hemoglobin deferral in a large retrospective cohort of plasmapheresis donors and the influence factors of return for a subsequent donation in China

Background and ObjectivesSome plasmapheresis donors were deferred from donating when they did not meet hemoglobin (Hb) criteria. The purpose of this retrospective analysis was to explore the characteristics of the low hemoglobin deferral (LHD) in plasmapheresis donors and identify at-risk donors of LHD, so as to enhance donor safety and improve donation service satisfaction of the plasmapheresis centers. Materials and MethodsThis multi-center survey was carried out from 2018 until 2020 on all plasmapheresis donors from 18 plasmapheresis centers in three provinces of China. Donor demographics and information were retrieved. A Cochran-Mantel-Haenszel Method was used to test the association between LHD and risk factors while controlling for difference geographic information of donors. Logistic regression analysis was used to explore the influence factors of return for a subsequent donation. ResultsA total of 497,039 participants were included. The female LHD rate was 0.15%, and male LHD rate was 0.01%. The most important risk factor for predicting the possibility of LHD in females was age between 41 to 50 years old. Donation in the winter was a protective factor from LHD. The number of donations in the previous 12 months were more likely to meet the Hb parameters and continue to donate. ConclusionsWe need to focus on premenopausal women, increase recruitment in winter and take necessary interventions in other seasons. The LHD donors who had more donations in previous 12 months, the more likely they were to meet the Hb conditions again and continue to donate.

Personalized medicine comes to a blood center near you

Personalized medicine comes to a blood center near you

Impact of a post-donation hemoglobin testing strategy on efficiency and safety of whole blood donation in England: A modeling study.

Deferrals due to low hemoglobin are time-consuming and costly for blood donors and donation services. Furthermore, accepting donations from those with low hemoglobin could represent a significant safety issue. One approach to reduce them is to use hemoglobin concentration alongside donor characteristics to inform personalized inter-donation intervals. We used data from 17,308 donors to inform a discrete event simulation model comparing personalized inter-donation intervals using "post-donation" testing (i.e., estimating current hemoglobin from that measured by a hematology analyzer at last donation) versus the current approach in England (i.e., pre-donation testing with fixed intervals of 12-weeks for men and 16-weeks for women). We reported the impact on total donations, low hemoglobin deferrals, inappropriate bleeds, and blood service costs. Personalized inter-donation intervals were defined using mixed-effects modeling to estimate hemoglobin trajectories and probability of crossing hemoglobin donation thresholds. The model had generally good internal validation, with predicted events similar to those observed. Over 1 year, a personalized strategy requiring ≥90% probability of being over the hemoglobin threshold, minimized adverse events (low hemoglobin deferrals and inappropriate bleeds) in both sexes and costs in women. Donations per adverse event improved from 3.4 (95% uncertainty interval 2.8, 3.7) under the current strategy to 14.8 (11.6, 19.2) in women, and from 7.1 (6.1, 8.5) to 26.9 (20.8, 42.6) in men. In comparison, a strategy incorporating early returns for those with high certainty of being over the threshold maximized total donations in both men and women, but was less favorable in terms of adverse events, with 8.4 donations per adverse event in women (7.0, 10,1) and 14.8 (12.1, 21.0) in men. Personalized inter-donation intervals using post-donation testing combined with modeling of hemoglobin trajectories can help reduce deferrals, inappropriate bleeds, and costs.

The effectiveness of iron education through a mobile application on donor return after deferral for low hemoglobin.

Low hemoglobin level is a common cause of donor deferral and results in a huge loss of the donor pool. This study aimed to evaluate the effectiveness of a mobile application as an educational tool to enhance donor return and improve hemoglobin levels after deferral. This was an interventional study involving 382 blood donors who were deferred for low hemoglobin. The donors were divided equally into two groups: a control group and the intervention group. The control group received standard management for low hemoglobin deferral, which includes a short counseling session and a 1-month course of oral iron therapy. The intervention group used a mobile application in addition to standard management. The primary endpoint was the number of blood donors who returned during the 7 months of follow-up. The secondary endpoints were the hemoglobin increment at the first visit after the donors' deferral. The return rate was higher in the intervention group, with 81.2% of the donors returning in the 7 months of follow-up compared to 66% of the control group (p<0.001). Male and female donors had mean hemoglobin increments of 1.0 g/dL and 0.7 g/dL, respectively, in the intervention group, compared to decrements of 0.2 g/dL and 0.4 g/dL, respectively, in the control group (p<0.001). Multivariable analysis showed a significant association between intervention method, education level and donation status on donor return (p=0.015, p<0.001, and p<0.001, respectively). Higher return rate and greater hemoglobin increase in the interventional group could be attributed to features in the mobile application. Repeat donors had the highest odds of returning to donate, followed by those with a tertiary level of education, and those given the mobile application. This study showed that a mobile application was effective in enhancing donor return and increasing hemoglobin level among deferred blood donors on their first return.

Iron status of blood donors.

This review examines recent research on the prevalence and importance of iron deficiency in blood donors, and on efforts to mitigate it. Premenopausal females, teenagers, and high-frequency donors are at the highest risk for donation-induced iron deficiency, in both high-resource and low-resource settings. The physiology relating iron stores to hemoglobin levels and low hemoglobin deferral is well elucidated in blood donor populations, yet the clinical effects attributable to iron loss in the absence of anemia are challenging to identify. Expanded adoption of ferritin testing is improving donor management but may cause decreases in the blood supply from temporary donor loss. The potential for personalized donor management is emerging with development of computational models that predict individual interdonation intervals that aim to optimize blood collected from each donor while minimizing low hemoglobin deferrals. Measures to reduce iron deficiency are available that can be deployed on a standardized or, increasingly, personalized basis. Blood centers, regulators, and donors should continue to evaluate different tactics for addressing this problem, to obtain a balanced approach that is optimal for maintaining adequate collections while safeguarding donor health.

Whole blood donor behavior and availability after deferral: Consequences of a new ferritin monitoring policy.

BackgroundTo prevent (negative consequences of) temporary deferral due to low hemoglobin, the Dutch national blood service Sanquin introduced a ferritin monitoring policy in 2017. Ferritin is measured after the donation (as opposed to before donation for hemoglobin), and low ferritin levels lead to deferral of 6 (ferritin 15‐30 ng/mL) or 12 months (ferritin <15 ng/mL). We explored the consequences of this policy on donor behavior and availability.Study Design and MethodsWe included all Dutch whole blood donors who made a donation (attempt) between 13 November and 31 December 2017. At that point, the ferritin monitoring policy was randomly implemented in 8 of 29 regional clusters of collection centers. We extracted information from Sanquin's donor database about donors' deferrals, subsequent donation attempts, and donation cessation (up to 31 December 2019). Donors deferred for low ferritin were compared to those deferred for low hemoglobin or other reasons, as well as to donors who were not deferred.ResultsA total of 55 644 donors were included (11% deferred). For donor behavior, we found that donors deferred for low ferritin less often unsubscribed and switched to other donation types, yet also made fewer donations in the follow‐up period. For availability, we found they were less often deferred, yet they were unavailable to donate for a longer period.ConclusionResults suggest that the implementation of a ferritin monitoring policy may lead to a decrease in donor availability and reduced donations. However, the policy is successful in retaining more donors and reducing low hemoglobin deferrals.

&lt;p&gt;Blood Donor Deferral Analysis in Relation to the Screening Process: A Single-Center Study from Southern India with Emphasis on High Hemoglobin Prevalence&lt;/p&gt;

PurposeDonor deferral results in loss of potential, motivated blood donors, and thereby, availability of blood for needy patients. This study analyses the frequency and reasons for donor deferral, including high hemoglobin deferral, which is underreported in India.MethodsRetrospective analysis of the deferral record of whole blood donors from January 2014 to December 2018 was performed with respect to the pre-donation screening process at our center. Accordingly, the deferrals are categorized as stage1 – evaluation of Donor History Questionnaire (DHQ), stage 2 – medical examination, stage 3 – hemoglobin (Hb) check using copper sulfate method or a gradually implemented quantitative hemoglobin analyzer, and stage 4 – before phlebotomy. Donor demographic details, donation frequency, and deferral reasons were noted. Descriptive statistical analysis was performed using SPSS version 20 (IBM, USA).ResultsOf 99,680 pre-donation screenings, 10.6% was deferred. The highest deferral (56.02%) was at stage 3 (based on hemoglobin level) contributed by low (52.45%) and high (3.75%) hemoglobin deferrals against cut-off of 12.5 to 18 g/dl. High Hb was noted only in male donors when screened by hemoglobin analyzer. Further, a steady fall in low hemoglobin but a rise in high hemoglobin deferral rate owing to the gradual implementation of hemoglobin analyzer over the study period was noted. The deferrals in stage 1, 2, and 4 were 29.64%, 13.97%, and 0.36%, respectively. Overall, the deferral rate was higher in females (49.88%), and in first-time (13.63%), and 18 to 25 yrs age-group (4.25%) donors for low Hb, underweight, and tattooing/ear piercing.ConclusionInsights on donor deferral reasons promote proactive measures towards donor recruitment and retention. Further, donor hemoglobin screening by quantitative method, if followed uniformly by all blood centers across the country, will help identify the true prevalence of high hemoglobin in Indian blood donors and ensures donor safety.

Optimal individualized decision rules from a multi-arm trial: A comparison of methods and an application to tailoring inter-donation intervals among blood donors in the UK.

There is a growing interest in precision medicine where individual heterogeneity is incorporated into decision-making and treatments are tailored to individuals to provide better healthcare. One important aspect of precision medicine is the estimation of the optimal individualized treatment rule (ITR) that optimizes the expected outcome. Most methods developed for this purpose are restricted to the setting with two treatments, while clinical studies with more than two treatments are common in practice. In this work, we summarize methods to estimate the optimal ITR in the multi-arm setting and compare their performance in large-scale clinical trials via simulation studies. We then illustrate their utilities with a case study using the data from the INTERVAL trial, which randomly assigned over 20,000 male blood donors from England to one of the three inter-donation intervals (12-week, 10-week, and eight-week) over two years. We estimate the optimal individualized donation strategies under three different objectives. Our findings are fairly consistent across five different approaches that are applied: when we target the maximization of the total units of blood collected, almost all donors are assigned to the eight-week inter-donation interval, whereas if we aim at minimizing the low hemoglobin deferral rates, almost all donors are assigned to donate every 12 weeks. However, when the goal is to maximize the utility score that “discounts” the total units of blood collected by the incidences of low hemoglobin deferrals, we observe some heterogeneity in the optimal inter-donation interval across donors and the optimal donor assignment strategy is highly dependent on the trade-off parameter in the utility function.

Genetic and behavioral modification of hemoglobin and iron status among first-time and high-intensity blood donors.

Some people rapidly develop iron deficiency anemia following blood donation, while others can repeatedly donate without becoming anemic. Two cohorts of blood donors were studied. Participants (775) selected from a 2-year longitudinal study were classified into six analysis groups based on sex, donation intensity, and low hemoglobin deferral. Associations with iron supplement use, cigarette smoking, and four genetic variants of iron metabolism were examined at enrollment and with longitudinal regression models. An unbiased assessment of genetic variability and ability to repeatedly donate blood without experiencing low hemoglobin deferral was conducted on participants (13,403) in a cross-sectional study who were examined by genome wide association (GWA). Behaviors and genetic variants were associated with differences in hemoglobin and ferritin change following repeated donation. At least weekly iron supplement use was associated with improved status in first-time donors, while daily use was associated with improved status in high-intensity donors. Cigarette smoking was associated with 0.5 g/dL increased hemoglobin in high-intensity donors. A736V in TMPRSS6 was associated with a rapid drop in hemoglobin and ferritin in first-time females following repeated donation. Conversely, the protective TMPRSS6 genotype was not enriched among high-intensity donors. H63D in HFE was associated with increased hemoglobin in female high-intensity donors. However, no differences in genotype between first-time and high-intensity donors were found in GWA analyses. Behavioral and genetic modifiers contributed to first-time donor hemoglobin and iron status, while iron supplement use was more important than underlying genetics in high-intensity donors.

The Sting of Rejection: Deferring Blood Donors due to Low Hemoglobin Values Reduces Future Returns

Background: Roughly one quarter of short-term temporary deferrals (STTD) of blood donors are low-hemoglobin deferrals (LHD), i.e. STTD due to a hemoglobin (Hb) value falling below a cutoff of 125 g/L for female and 135 g/L for male donors. Since voluntarily donating blood is a prosocial activity, donors may perceive deferral as social exclusion, which can cause social pain, decrease self-esteem, and lead to antisocial behavior. However, little is known about the causal impacts of LHD on donor return. Study Design and Methods: We conducted a quasi-experiment with 80,060 donors invited to blood drives in the canton of Zurich, Switzerland, between 2009 and 2014. Within a narrow window of Hb values around the predetermined cutoff, the rate of LHD jumps discontinuously. This discontinuous jump allows us to quantify the causal effects of LHD on donor return, as it is uncorrelated with other unobserved factors that may also affect donor return. Results: We found different behavioral reactions to LHD for female and male donors. Female donors do not react to the first LHD. However, after any repeated LHD, they are 13.53 percentage points (p <0.001) less likely to make at least 1 donation attempt within the next 18 months and make 0.389 fewer donation attempts (p <0.001). Male donors react to the first LHD. They are 5.32 percentage points (p = 0.139) less likely to make at least 1 donation attempt over the next 18 months and make 0.227 (p = 0.018) fewer donation attempts. After any repeated LHD, male donors are 13.30 percentage points (p = 0.004) less likely to make at least 1 donation attempt and make 0.152 (p = 0.308) fewer donation attempts. Conclusion: LHD have detrimental impacts on donor return, especially if they occur repeatedly – suggesting that avoiding false LHD and helping donors to better cope with them helps to maintain the pool of prospective donors.

Blood Donation and Iron Deficiency

In the United States about 40,000 people per day donate blood. Donors are from all racial/ethnic backgrounds and range in age from 16 to over 80 years old. They are allowed to repeatedly donate blood every 56 days, as long as they maintain their hemoglobin above 12.5 g/dL for females or 13.0 g/dL for males. Although each donation removes 200-250 mg of iron from the donor, testing for iron deficiency is not performed. Thus, blood donation can be viewed as a large clinical study to examine the physiological effects of repeated phlebotomy of approximately 10% of an individual's blood volume. In addition, blood donors are altruistic by nature and typically are very willing to participate in research studies. We have utilized this rich clinical population to perform studies on iron metabolism and red blood cell biology in an otherwise healthy population. These include a study of over 750,000 donors to define the demographics of anemia. A study detailing the body's response to blood donation, finding that recovery of iron stores takes over 90 days, if the donor takes daily iron pills following donation, and much longer if they do not. Despite this long time for recovery of iron stores, some donors are capable of repeatedly donating blood every 56 days for several years without experiencing a low hemoglobin deferral. Study of these “superdonors” has identified potential associated genetic variants and behaviors that allow frequent donation without development of anemia. Teenagers are allowed to donate blood in the United States at the same 56 day donation frequency and hemoglobin cut-off values as adults even though they have increased iron requirements for continued growth and neurocognitive development. A study detailing the impact of blood donation on teenager hemoglobin and iron stores has found that they are more susceptible to iron deficiency than adults, and, therefore, should have extra protections to prevent donation-induced iron deficiency. DisclosuresMast:Novo Nordisk: Research Funding.

Blood, sweat, and tears: Red Blood Cell-Omics study objectives, design, and recruitment activities.

The Red Blood Cell (RBC)-Omics study was initiated to build a large data set containing behavioral, genetic, and biochemical characteristics of blood donors with linkage to outcomes of the patients transfused with their donated RBCs. The cohort was recruited from four US blood centers. Demographic and donation data were obtained from center records. A questionnaire to assess pica, restless leg syndrome, iron supplementation, hormone use, and menstrual and pregnancy history was completed at enrollment. Blood was obtained for a complete blood count, DNA, and ferritin testing. A leukocyte-reduced RBC sample was transferred to a custom storage bag for hemolysis testing at Storage Days 39 to 42. A subset was recalled to evaluate the kinetics and stability of hemolysis measures. A total of 13,403 racially/ethnically diverse (12% African American, 12% Asian, 8% Hispanic, 64% white, and 5% multiracial/other) donors of both sexes were enrolled and ranged from 18 to 90 years of age; 15% were high-intensity donors (nine or more donations in the prior 24 mo without low hemoglobin deferral). Data elements are available for 97% to 99% of the cohort. The cohort provides demographic, behavioral, biochemical, and genetic data for a broad range of blood donor studies related to iron metabolism, adverse consequences of iron deficiency, and differential hemolysis (including oxidative and osmotic stress perturbations) during RBC storage. Linkage to recipient outcomes may permit analysis of how donor characteristics affect transfusion efficacy. Repository DNA, plasma, and RBC samples should expand the usefulness of the current data set.

The operational implications of donor behaviors following enrollment in STRIDE (Strategies to Reduce Iron Deficiency in blood donors).

Donor behaviors in STRIDE (Strategies to Reduce Iron Deficiency), a trial to reduce iron deficiency, were examined. Six hundred ninety-two frequent donors were randomized to receive either 19 or 38 mg iron for 60 days or an educational letter based on their predonation ferritin. Compliance with assigned pills, response to written recommendations, change in donation frequency, and future willingness to take iron supplements were examined. Donors who were randomized to receive iron pills had increased red blood cell donations and decreased hemoglobin deferrals compared with controls or with pre-STRIDE donations. Donors who were randomized to receive educational letters had fewer hemoglobin deferrals compared with controls. Of those who received a letter advising of low ferritin levels with recommendations to take iron supplements or delay future donations, 57% reported that they initiated iron supplementation, which was five times as many as those who received letters lacking a specific recommendation. The proportion reporting delayed donation was not statistically different (32% vs. 20%). Of donors who were assigned pills, 58% reported taking them "frequently," and forgetting was the primary reason for non-compliance. Approximately 80% of participants indicated that they would take iron supplements if provided by the center. Donors who were assigned iron pills had acceptable compliance, producing increased red blood cell donations and decreased low hemoglobin deferrals compared with controls or with pre-STRIDE rates. The majority of donors assigned to an educational letter took action after receiving a low ferritin result, with more donors choosing to take iron than delay donation. Providing donors with information on iron status with personalized recommendations was an effective alternative to directly providing iron supplements.

Season and time of day affect capillary blood hemoglobin level and low hemoglobin deferral in blood donors: analysis in a national blood bank

Low hemoglobin (Hb) is the most common reason for temporary blood donor deferral. However, factors that affect Hb measurement may not portray donor health but reflect external circumstances. The effects of season, time of day, donor age, ABO, and D on capillary blood Hb level (cHb) and low Hb deferral were analyzed in 1,396,645 donor registrations from the years 2010 to 2014 in a national blood bank. cHb was lower in the summer (July mean 154.1 g/L in men, 139.6 g/L in women) and in the evening (7 pm mean 153.8 g/L in men, 138.9 g/L in women) than in the winter (January mean 156.9 g/L in men, 141.8 g/L in women) and in the morning (11 am mean 157.2 g/L in men, 142.8 g/L in women; all p < 0.0001). This affected donor deferral due to low Hb, with 7.8% donors deferred in July at 7 pm and 1.6% deferred in January at 11 am (p < 0.0001). With age, cHb increased in women and decreased in men. The lowest cHb was observed in blood group A (mean 154.9 g/L in men, 140.3 g/L in women) and the highest in blood group B (mean 156.6 g/L in men, 141.5 g/L in women). D had no practically significant effect on cHb. External factors, which do not reflect donor health, affect cHb and donor deferral due to low Hb. These factors should be considered when donor eligibility guidelines and procedures are developed.

Generalizability of Dutch Prediction Models for Low Hemoglobin Deferral: A Study on External Validation and Updating in Swiss Whole Blood Donors

Background: Sex-specific prediction models for low hemoglobin (Hb) deferral have been developed in Dutch whole blood donors. In this study, we validated and updated the models in a cohort of Swiss whole blood donors. Methods: Prospectively collected data from 53,772 Swiss whole blood donors were used. The predictive performance of the Dutch models was assessed in terms of calibration (agreement between predicted probabilities and observed frequencies) and discrimination (ability to discriminate between deferred and approved donors). The models were updated by revising the strength of the individual predictors in the models. Results: A total of 1,065 men (3.3%) and 2,063 women (9.7%) were deferred from donation because of a low Hb level. Validation in Swiss donors demonstrated underestimation of predicted risks and significantly lower discriminative ability. The predictive effects of most predictors were weaker in Swiss donors. Updating the models increased the calibration for both men and women, and slightly increased the discriminative ability in men. Conclusion: Validation of the Dutch prediction models in Swiss whole blood donors showed lower, though adequate performance. In general, the Dutch prediction models can reliably predict the risk of Hb deferral, although for application in other countries small adaptations are necessary.

Minimum donation intervals should be reconsidered to decrease low hemoglobin deferral in whole blood donors: an observational study.

Most donor deferrals are due to low hemoglobin (Hb) levels. Previously measured Hb levels and donation intervals are known to be associated with Hb deferral. However, this relationship has never been quantified. In this study, we related the prevalence of Hb deferral to previously measured Hb levels and donation intervals. A total of 220,946 whole blood donors were categorized into groups based on their Hb level at the previous donation and on the time interval since the previous donation. For each group, the prevalence of Hb deferral was assessed. Hb deferral rates were higher when Hb levels at the previous donation were lower and donation intervals were shorter. With a donation interval shorter than 3 months, the prevalence of Hb deferral was below the 10% threshold only when the previous Hb level was at least 0.3 mmol/L above the cutoff level for donation. To maintain appropriate Hb levels, the minimum donation interval of 56 days is only sufficient for donors with Hb levels far above the cutoff level for donation. Protocols for minimum donation intervals should be reconsidered and may be based on previously measured Hb levels. This may result in a decrease of low Hb deferral.

The health implications of low hemoglobin deferral in infrequent blood donors

The causes of anemia in infrequent blood donors deferred for low hemoglobin (Hb) are not well known. We sought to assess this via surveys of infrequent, non-menstruating deferred blood donors at two institutions, BloodCenter of Wisconsin and Puget Sound Blood Center. Men at least 18 years of age and women at least 50 years of age who were deferred for low Hb (≤12.5 g/dL), had not more than one donation in the year prior to deferral, and did not successfully donate in the 3 months after their deferral were surveyed. The total response rate was 380 donors or 34% of those contacted. Of the respondents, 141 had sought medical advice about their low Hb. Of these, 90 were confirmed to have anemia and 13 reported serious disease requiring medical intervention, including mantle cell lymphoma, multiple myeloma, and gastrointestinal bleeding. A small but concerning number of infrequent blood donors deferred for low Hb have an underlying illness that is severe and would benefit from medical attention. Donors deferred for low Hb who have a high risk for serious underlying illness should be provided targeted educational information advising them to seek additional medical care.

Low hemoglobin deferral in blood donors

Low hemoglobin deferral occurs in about 10% of attempted whole blood donations and commonly is a consequence of iron deficiency anemia. Pre-menopausal women often have iron deficiency anemia caused by menstruation and pregnancy and have low hemoglobin deferral on their first donation attempt. Frequent donors also develop iron deficiency and iron deficiency anemia because blood donation removes a large amount of iron from the donor and the 56-day minimum inter-donation interval for donors in the United States is not sufficient for recovery of hemoglobin and iron stores. Other causes for low hemoglobin deferral range from a medically insignificant deferral of a woman with hemoglobin between 12.0 and 12.4 g/dL, which is within the normal reference range but below the 12.5 g/dL needed to donate blood, to anemia caused by an unrecognized malignancy in a "healthy" individual attempting to donate blood. The diverse causes of anemia in blood donors make it difficult to provide accurate information to donors about the cause of their low hemoglobin deferral and complicate implementation of programs to prevent them by blood collecting agencies. This article reviews how hemoglobin is measured and the demographics and causes of low hemoglobin deferral in blood donors. It provides recommendations for how blood collection agencies can provide donors with accurate information about the cause of their deferral and discusses programs that can be implemented to decrease these deferrals in regular donors.

External validation and updating of a Dutch prediction model for low hemoglobin deferral in Irish whole blood donors

Recently, sex-specific prediction models for low hemoglobin (Hb) deferral have been developed in Dutch whole blood donors. In the present study, we validated and updated the models in a cohort of Irish whole blood donors. Prospectively collected data from 45,031 Irish whole blood donors were used. Hb cutoff levels for donation were approximately 0.35 mmol/L lower in Ireland than the Dutch cutoff levels (8.07 mmol/L vs. 8.40 mmol/L in men; 7.45 mmol/L vs. 7.80 mmol/L in women). The predictive performance of the models was assessed with calibration plots, calibration-in-the-large, and the concordance (c)-statistic. The models were updated by revising the strength of the individual predictors in the models. A total of 613 men (2.4%) and 1624 women (8.4%) were deferred from donation because of a low Hb level. Validation demonstrated underestimation of predicted risks and lower c-statistics for men and women compared to the Dutch cohort. The strength of most predictive factors, particularly previous Hb level, was lower in Irish donors. The updated models showed a c-statistic of 0.83 (95% confidence interval [CI], 0.81-0.84) for men and 0.76 (95% CI, 0.74-0.77) for women. The performance of Dutch prediction models for Hb deferral was limited when validated in Irish whole blood donors. Updating the models resulted in different predictor effects. This improved mainly the model calibration; the improvement in discrimination was small.