SummaryBackgroundLimits on the frequency of whole blood donation exist primarily to safeguard donor health. However, there is substantial variation across blood services in the maximum frequency of donations allowed. We compared standard practice in the UK with shorter inter-donation intervals used in other countries.MethodsIn this parallel group, pragmatic, randomised trial, we recruited whole blood donors aged 18 years or older from 25 centres across England, UK. By use of a computer-based algorithm, men were randomly assigned (1:1:1) to 12-week (standard) versus 10-week versus 8-week inter-donation intervals, and women were randomly assigned (1:1:1) to 16-week (standard) versus 14-week versus 12-week intervals. Participants were not masked to their allocated intervention group. The primary outcome was the number of donations over 2 years. Secondary outcomes related to safety were quality of life, symptoms potentially related to donation, physical activity, cognitive function, haemoglobin and ferritin concentrations, and deferrals because of low haemoglobin. This trial is registered with ISRCTN, number ISRCTN24760606, and is ongoing but no longer recruiting participants.Findings45 263 whole blood donors (22 466 men, 22 797 women) were recruited between June 11, 2012, and June 15, 2014. Data were analysed for 45 042 (99·5%) participants. Men were randomly assigned to the 12-week (n=7452) versus 10-week (n=7449) versus 8-week (n=7456) groups; and women to the 16-week (n=7550) versus 14-week (n=7567) versus 12-week (n=7568) groups. In men, compared with the 12-week group, the mean amount of blood collected per donor over 2 years increased by 1·69 units (95% CI 1·59–1·80; approximately 795 mL) in the 8-week group and by 0·79 units (0·69–0·88; approximately 370 mL) in the 10-week group (p<0·0001 for both). In women, compared with the 16-week group, it increased by 0·84 units (95% CI 0·76–0·91; approximately 395 mL) in the 12-week group and by 0·46 units (0·39–0·53; approximately 215 mL) in the 14-week group (p<0·0001 for both). No significant differences were observed in quality of life, physical activity, or cognitive function across randomised groups. However, more frequent donation resulted in more donation-related symptoms (eg, tiredness, breathlessness, feeling faint, dizziness, and restless legs, especially among men [for all listed symptoms]), lower mean haemoglobin and ferritin concentrations, and more deferrals for low haemoglobin (p<0·0001 for each) than those observed in the standard frequency groups.InterpretationOver 2 years, more frequent donation than is standard practice in the UK collected substantially more blood without having a major effect on donors' quality of life, physical activity, or cognitive function, but resulted in more donation-related symptoms, deferrals, and iron deficiency.FundingNHS Blood and Transplant, National Institute for Health Research, UK Medical Research Council, and British Heart Foundation.

BACKGROUND: Predonation hemoglobin (PDH) is used to safeguard donors’ welfare, and low hemoglobin (Hb) is known to be the most frequent reason for donor deferral. A study was initiated to assess the PDH and iron status of blood donors in Hong Kong. STUDY DESIGN AND METHODS: This observational study was designed with four groups of whole blood donors invited (Group 1—eligible first time donors, Group 2—eligible repeat donors with zero or one donation in preceding 12 months, Group 3—eligible repeat donors with at least two donations in preceding 12 months, Group 4—repeat donors being deferred for low PDH). Predonation blood samples were obtained for blood counts and iron status. Mann‐Whitney test, Kruskal‐Wallis test, and chi‐square test for trend were applied for statistical analysis. RESULTS: A total of 836 donors were recruited, of which 35 were excluded because of hemoglobinopathy. An inverse relationship between serum ferritin level and number of donations in the preceding 12 months was observed in both sexes. Iron deficiency was significantly seen in 35.1% of male and 65.3% of female deferred donors. More importantly, up to 7.2, 5.8, and 29.5% of the female donors in Groups 1, 2, and 3 were found to be iron deficient despite having a high enough PDH. CONCLUSION: This is the first study to assess PDH and iron status in Chinese blood donors. Iron depletion is noted with increasing number of blood donations in the preceding 12 months. Advice on iron repletion is a necessary step for donor welfare and strategies should be developed to ensure that donors have adequate PDH.