Other pager users were the North West Ambulance Service (NWAS) and Northern Ireland Ambulance Service (NIAS), which sent messages with details for crews such as addresses, patient ages, and medical information.
Both services said the messages did not include patients’ names, while NWAS said pagers had now been fully withdrawn and for NIAS largely withdrawn.
Health and social care in Northern Ireland is a devolved matter, and therefore the responsibility of the Department of Health NI, rather than the UK Department of Health.
The has approached Department of Health NI for comment.
A spokesperson for NIAS said it “will always recognise best practice across the UK”.
An Information Commissioner Office spokesperson said: “People’s medical data is highly sensitive information, not only do people expect it to be handled carefully and securely, organisations also have a responsibility under the law.
“NHS Blood and Transplant reported an incident to us and we are making inquiries.”
The Department for Health and Social Care said the NHS has “made progress in replacing outdated technology and is working to ensure staff have access to secure, reliable digital tools that support safe, high-quality patient care”.