A senior Northern Ireland civil servant has apologised after hundreds of neurology patients were recalled for further testing.
An independent inquiry has been launched following a probe into the work of a consultant neurologist in Belfast.
It followed the year-long examination by the Royal College of Physicians of patient notes relating to the work of Dr Michael Watt.
The permanent secretary at Stormont's health department, Richard Pengelly, said the health and social care services "apologised unreservedly" after standards of care fell short.
"This issue has undoubtedly caused a great deal of distress to patients and their loved ones.
"On behalf of the entire health and social care system I want to apologise unreservedly for that - the reality is that we all feel diminished when the high standards the public demands of our service are not met."
Neurology involves treating brain conditions including multiple sclerosis and Parkinson's.
The recall of 2,500 people by Belfast Health and Social Care Trust has raised concerns about potential misdiagnosis.
Mr Pengelly added: "In recent weeks and months, prompted by other events, there has rightly been a focus on whether our service is sufficiently open and transparent, the extent to which we take responsibility for our mistakes and, more importantly, learn from them.
"I want the public to be in no doubt that we are sincere in our efforts to learn from past, and more recent, events.
"The standard of care provided has fallen short of the one we have set, and indeed the standard the public have the right to expect."
He assured the public that health authorities and the independent sector were working hard on a number of fronts to address this rapidly.
"I do want to emphasise that that will be an open and robust process, and anything less than complete co-operation from all parts of the system will simply not be acceptable.
"One further strand to our work is that, recognising that the lapse in standards will have had potentially profound implications for some people, I am also commissioning work on what redress measures need to be considered.
"Conclusions about this aspect will clearly be an issue for returning ministers, but it is important we start that work now."