Hospitals across the State have admitted to a catalogue of errors in the way in which they transfused blood products to patients over the last year.
A number of patients got the wrong type of blood while others got too much.
One elderly woman who was "over-transfused" subsequently died, and the blood bank, which monitors such adverse incidents, said yesterday that the transfusion may have contributed to her death. It did not know if the woman's family was ever informed.
It said there were 155 reports to it of adverse events involving transfusions in hospitals in 2002 - up 11 on the previous year - and 47 per cent of them were regarded as life-threatening or as incidents which had the potential to cause permanent injury. Twelve of the incidents involved children.
The mistakes included:
Three cases where the wrong patient's blood was sampled, leading to blood of a different ABO group being transfused.
Blood cross-matched for one patient was collected from the blood fridge and transfused to a different patient.
In two cases, the wrong component was transfused where platelets were requested instead of plasma and vice versa.
In six cases, transfusion was based on incorrect haematology results.
There were 10 cases of inappropriate transfusions.
In two other cases, an inappropriately large dose of platelets was given in error because of misunderstanding of dosage guidelines.
In another case, rhesus positive plasma was issued to a rhesus negative patient "due to a communication error".
Four rhesus-positive women received anti-D in error, and in one of these cases the anti-D was given to the wrong patient.
Six rhesus-negative women who did not require anti-D during their latest pregnancy received it.
The errors are chronicled in the annual report of the National Haemovigilance Office for 2002 which was published by the Irish Blood Transfusion Service yesterday.
It found more than half the errors - some 52 per cent - where incorrect blood components were transfused "could have been detected and prevented during the final bedside checking procedure".
The report reveals there were also three incidents in which transfusions were suspected of transmitting infections including hepatitis B and hepatitis C. However, investigations by the blood bank ruled out transfusion-transmitted infection in two of the cases. The third case, that of a person with hepatitis B, is still being investigated.
Furthermore, there were 39 reports of patients suffering adverse reactions to transfusions, mostly to platelets. Some of these patients were on multiple medications which, the report said, made it difficult to be certain what caused the reaction.
Dr Emer Lawlor, director of the National Haemovigilance Office, said the 155 adverse incidents were out of a total of more than 168,000 blood products issued for transfusion by the blood bank in 2002.
She added that most of the incidents appeared at a glance to be due to human error, but when looked at more closely they were more likely due to systems failures.
She called for increased investment to improve these systems, which would include computerised patient records systems.
Commenting on the case of the woman who may have died as a result of her transfusion, she said there were problems with transfusing elderly patients, and hospitals needed to be careful in this regard.
She added that there was always a residual risk of transfusion-transmitted infection. For hepatitis B it was one in 200,000 and for HIV one in five million. Transfusing a wrong blood type could kill a patient and was extremely serious.
Her report makes several recommendations. It says it is desirable to transfuse only when adequate staff are on duty, avoiding night-time transfusions; there should be ongoing education and training of medical and nursing staff in correct blood sampling techniques; all requests for blood products should ideally be in writin; and it may be prudent to transfuse only one unit of blood in each 24-hour period in elderly patients.