Trial reportTrials2014
The INTERVAL trial to determine whether intervals between blood donations can be safely and acceptably decreased to optimise blood supply: study protocol for a randomised controlled trial.
Trial report in Trials, 2014. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 81 papers, 9 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
81 citing papers in PubMed, 9 syntheses or guidelines pooled it.
- What is the impact of whole-blood donation frequency on donor health? A systematic review.Vox sanguinis · 2026Pooled it
- Association of circulating fatty acids with cardiovascular disease risk: analysis of individual-level data in three large prospective cohorts and updated meta-analysis.European journal of preventive cardiology · 2025Pooled it
- The health impacts of blood donation: a systematic review of donor and non-donor perceptions.Blood transfusion = Trasfusione del sangue · 2024Pooled it
- Pooled it
- Pooled it
- Mendelian randomization analysis of plasma levels of CD209 and MICB proteins and the risk of varicose veins of lower extremities.PloS one · 2022Pooled it
- The influence of rare variants in circulating metabolic biomarkers.PLoS genetics · 2020Pooled it
- Assessing the causal association of glycine with risk of cardio-metabolic diseases.Nature communications · 2019Pooled it
- Fifteen new risk loci for coronary artery disease highlight arterial-wall-specific mechanisms.Nature genetics · 2017Pooled it
- Cost-effectiveness of alternative minimum recall intervals between whole blood donations.PloS one · 2022Trial
- Longer-term efficiency and safety of increasing the frequency of whole blood donation (INTERVAL): extension study of a randomised trial of 20 757 blood donors.The Lancet. Haematology · 2019Trial
- Effect of communicating phenotypic and genetic risk of coronary heart disease alongside web-based lifestyle advice: the INFORM Randomised Controlled Trial.Heart (British Cardiac Society) · 2019Trial
- The associations between the response efficacy and objective and subjective change in physical activity and diet in the Information and Risk Modification trial.Public health · 2018Trial
- Efficiency and safety of varying the frequency of whole blood donation (INTERVAL): a randomised trial of 45 000 donors.Lancet (London, England) · 2017Trial
- Trial
- Trial
- A Large-Scale Multi-omics Polygenic Risk Score Analysis Identified Candidate Biomarkers Associated with Heel Bone Mineral Density.Calcified tissue international · 2026Article
- Iron status modulates immune cell proportions to drive epigenetic age acceleration: A 2-step Mendelian randomization study.Medicine · 2026Article
- Integrating human plasma proteomes with genome-wide association data implicates novel proteins and drug targets for rheumatoid arthritis.Clinical proteomics · 2026Article
- Linear and non-linear proteome-wide association studies provide novel insight into venous thromboembolism.Nature communications · 2025Article
21 more citing papers are in PubMed but not listed here.
Corrections and comments
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Authors and funding
13 authors.
Funding
Abstract
backgroundAgeing populations may demand more blood transfusions, but the blood supply could be limited by difficulties in attracting and retaining a decreasing pool of younger donors. One approach to increase blood supply is to collect blood more frequently from existing donors. If more donations could be safely collected in this manner at marginal cost, then it would be of considerable benefit to blood services. National Health Service (NHS) Blood and Transplant in England currently allows men to donate up to every 12 weeks and women to donate up to every 16 weeks. In contrast, some other European countries allow donations as frequently as every 8 weeks for men and every 10 weeks for women. The primary aim of the INTERVAL trial is to determine whether donation intervals can be safely and acceptably decreased to optimise blood supply whilst maintaining the health of donors. METHODS/
designINTERVAL is a randomised trial of whole blood donors enrolled from all 25 static centres of NHS Blood and Transplant. Recruitment of about 50,000 male and female donors started in June 2012 and was completed in June 2014. Men have been randomly assigned to standard 12-week versus 10-week versus 8-week inter-donation intervals, while women have been assigned to standard 16-week versus 14-week versus 12-week inter-donation intervals. Sex-specific comparisons will be made by intention-to-treat analysis of outcomes assessed after two years of intervention. The primary outcome is the number of blood donations made. A key secondary outcome is donor quality of life, assessed using the Short Form Health Survey. Additional secondary endpoints include the number of 'deferrals' due to low haemoglobin (and other factors), iron status, cognitive function, physical activity, and donor attitudes. A comprehensive health economic analysis will be undertaken. DISCUSSION: The INTERVAL trial should yield novel information about the effect of inter-donation intervals on blood supply, acceptability, and donors' physical and mental well-being. The study will generate scientific evidence to help formulate blood collection policies in England and elsewhere.
trial registrationCurrent Controlled Trials ISRCTN24760606, 25 January 2012.
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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.