An investigation has been launched after ten seriously ill patients in Northern Ireland receiving dialysis treatment suffered unexpected complications.
Dialysis filters the blood and can be used during treatment of kidney failure.
The cause of the problem has not yet been established.
A spokesman for the four health trusts said dialysis units across Northern Ireland were participating in a full and thorough investigation of all of these cases.
In the interim staff are being advised to be vigilant to the possibility of further cases and to the need for early identification and treatment.
The patients affected have recovered and all receiving dialysis have been contacted and advised of symptoms to look out for.
The illness is called haemolysis and can cause abdominal or chest pain, vomiting, shivering or flushing and rising blood pressure.
It involves the release of haemoglobin into the surrounding fluid of the blood, plasma.
