About the study

Between June 2012 and June 2014, the INTERVAL study recruited about 25,000 men and about 25,000 women at NHS Blood and Transplant (NSHBT) blood donation centres across England (to see locations click here).

During the study participants are asked to give blood either at usual donation intervals or more frequently. Men donate every 12, 10 or 8 weeks and women every 16, 14 or 12 weeks.

At the end of the study period, we will compare the amount of blood donated and measures of well-being in people asked to give blood at standard intervals versus those asked to give blood more frequently.