Phase II

What’s happened so far on INTERVAL?

The INTERVAL trial was set up as a 2-year study to assess the impact of shorter donation intervals on the health and well-being of blood donors and on blood services. In the last two years, 50,000 donors have been recruited into the study. This remarkable achievement is thanks to donors like you who have supported this research.

Why is Phase II happening now?

The last participant was recruited in mid-June 2014. The reason for Phase II is to make maximum scientific use of the time between now and June 2016, when the last participants recruited into INTERVAL are due to end their 2-year involvement in the study. We are now inviting interval participants, like you, to keep donating blood until June 2016 at the same interval you have been assigned to give blood as part of the INTERVAL study.

Why is Phase II needed?

Rather than stopping your involvement at your 2-year anniversary of joining INTERVAL, we would like you to consider getting involved in INTERVAL Phase II in order to provide extra valuable information to help us develop strategies to enhance the health of blood donors and optimise blood services.

Phase II will enhance the information we have already planned to collect during the 2-year INTERVAL study. In particular, this extension period will enable researchers to work out if donors find it acceptable to donate more or less often beyond a duration of two years. It will also evaluate the impact of different donation frequencies on the health and well-being of donors and on blood services over this longer period. The Phase II extension will provide an opportunity to tackle an additional question: what is the impact on donors’ health and on blood services of a more active approach to managing appointments for blood donations? In INTERVAL, the approach has been somewhat “more active” than the approach routinely used by NHS Blood and Transplant. For example, INTERVAL has provided donors with more frequent reminders to attend appointments than is routine in the blood service. However, the impact of using these different approaches is not known. So, to compare these approaches directly in a rigorous manner, we will randomly allocate donors who join INTERVAL Phase II to receive reminders about their donation appointments by either an approach very similar to that used during the first phase of INTERVAL, or an approach which involves less frequent reminders through NHSBT’s routine reminder system.

What will be involved?

If you choose to join INTERVAL Phase II, you will:

  • Continue to give blood at one of the 24 fixed Donor Centres across England
  • Attend your donation appointments, until June 2016, at your previously allocated study interval, i.e. 8, 10, or 12 weeks for men and 12, 14, or 16 weeks for women
  • Make your appointments through the INTERVAL Study Administration Team (ISAT). You won’t be able to make your appointments through NHSBT’s National Call Centre, Donor Portal or Website
  • Receive reminders about your donation appointments by either an approach very similar to that used during the first phase of INTERVAL or an approach which involves less frequent reminders
  • The type of reminders you receive will be decided by an entirely random process
  • Continue to complete questionnaires every 6 months until June 2016

You may also be asked to:

  • Give a small research blood sample at the end of the study
What should I do if I want to take part?

You will be sent an email invitation with a link to an online information sheet and consent form. Depending what stage you have reached in the 2-year INTERVAL study, you may receive this email either several weeks before or shortly after your final study donation before your 2-year anniversary. If you decide to join the study after reading the online information, all you need to do is complete our online consent form.

What happens immediately after I enrol in the study?

A few days after enrolling we will send you a welcome email which will include contact details for your future appointments and for any further questions you have about the study.

What standards are in place to protect me and the data / samples I provide?

INTERVAL Phase II will maintain the standards that have been in place during the first phase of INTERVAL to protect you and your data. This includes regular review by an independent safety committee.

I am deferred from donating blood, can I join?

Yes. If you are deferred from donating blood you are able to continue to make an important contribution to the study’s findings. If you are able to give blood again during your participation in Phase II, we will ask you to do so at your previously allocated donation interval.

I’m a platelet donor, but I’m still on the INTERVAL study, can I join?

No, I’m afraid not. But we would like to thank you for your help with our research so far and your valuable contributions to the donation service.

How long do I have to decide whether to join Phase II?

You have 21 days to complete the online consent form starting from the date that you receive our email invitation to join Phase II. If you lose the email we can resend it, but only within the 21 day consenting period. If you are in any doubt please call the Helpline on 0800 064 0089.

Will I know which type of appointment reminders I have been randomised to?

No. It is possible that you may get reminders about your appointments as you previously did on INTERVAL (i.e. through ISAT) or through NHSBT’s reminder systems.

I’d like to help your research but I don’t want to keep donating at my assigned study interval.

That is fine, if you decide not to join INTERVAL Phase II you can still help us with our future research. You can do this by giving the INTERVAL researchers permission to retrieve, in the long-term, study-specific anonymised data from your donor record. These data will be used by the study investigators to gain more information on the effect of donation frequency on blood supply and donor well-being. There is an option to consent to this level of involvement in our research within the online information for Phase II.

How long is Phase II?

Phase II will finish in June 2016.

I don’t want to consent online, can you send me a copy in the post?

I’m afraid not. Due to practical considerations, the consenting process has been designed to be completed online only.

Do I automatically become part of Phase II?

No. To join Phase II you must click the link in the invitation email that we send you and fill out the online consent form.

Who do I contact if I have any further questions or concerns?

If you have any more questions or concerns about INTERVAL Phase II please contact the Helpdesk on 0800 064 0089 or email