The BTRU in Donor Health and Genomics offers a fundamentally new approach to donor health research. In keeping with the NIHR BTRU call for approaches that combine “laboratory and population research”, the unit combines the precision of molecular measurements with the power of large-scale studies of donors. The deep integration of cutting-edge technologies (e.g., “multi-omics” assays) with large, well-characterised, and serially-assessed donor population studies will yield findings of considerable value and novelty to inform decision-making by NHSBT. To ensure a clinically relevant and hypothesis-driven approach, we will focus sharply on donation-related health outcomes and on biological pathways related to iron homeostasis. To ensure wide-angle consideration of determinants of donor health, each theme of our proposed BTRU will consider extensive genomic, biochemical, lifestyle and other potential risk factors. To harvest the complex and rich data that will emerge from our studies in a rigorous and principled manner, our team includes world leaders in epidemiology and biostatistics and builds on innovative approaches that we have previously developed.


The INTERVAL Trial (ISRCTN24760606) is an open randomised pragmatic trial to determine whether blood can be safely and acceptably collected from donors by NHSBT more frequently than present practice and at similar intervals to current customs in some other European countries. The INTERVAL BioResource provides a powerful and detailed research platform to enable further cost-effective and highly informative studies of donor health.

In the UK, men donate blood every 12 weeks and women donate every 16 weeks. However, there has never been a large scale study researching whether or not this standard interval is optimal for ensuring donor health while maintaining adequate blood supplies. Blood donation intervals also vary widely across the globe.

INTERVAL is an internationally unique study in donor health because it combines:

  • Large numbers of donors
  • Randomised comparisons of different inter-donation intervals
  • Serial collection of biological samples and clinical information from donors
  • Extensive genetic, haematological, biochemical and lifestyle characterisation of donors
  • Ascertainment of suspected iron-depletion side effects and other donation-related health outcomes
  • The ability to re-contact donors for further information (e.g. questionnaires)
  • The ability to link with electronic health records

Spring 2018 Newsletter

Visit the INTERVAL website for further information about the study.

The trial paper (2014).

Recruitment and representativeness of blood donors in the trial (2016).

The main study results, Efficiency and safety of varying the frequency of whole blood donation (INTERVAL): a randomised trial of 45000 donors (2017), have been published.

Press release: “New research shows that blood donors could safely give blood more frequently than is allowed at present. At the moment in the UK men can give blood every 12 weeks, women every 16 weeks. The new research demonstrates that in certain situations and for certain donors, shortening the donation interval is a viable approach for blood services to take.”


Results from INTERVAL have shown that more frequent blood donations from donors can be done without causing harm to donor health. These findings are likely to shape national and international blood donor policy. They have provided policy-makers with evidence that more frequent collection from donors than is now standard can be done over two years without causing harm to donor health, allowing better management of the supply to the NHS of units of blood with in-demand blood groups. The data also quantify the extent of iron depletion within two years of repeated donation, informing safety guidelines for countries (e.g., US, Germany, France) that allow more frequent donation than the UK.