The Blood Transfusion Service Board should have traced between 1986 and 1988 all recipients of blood from donors who subsequently tested HIV positive, but it did not do so, the tribunal heard.
The board's chief medical witness, Dr Emer Lawlor, said she could not explain why not.
Counsel for the tribunal, Mr Gerard Durcan SC, suggested to Dr Lawlor that the need for a "look-back" procedure should have been evident after the introduction of HIV screening by the BTSB in October 1985.
When Dr Lawlor pointed to the amount of effort a look-back took and the fact that the BTSB was short of staff, Mr Durcan said this might have been the case but no decision had been taken to conduct a look-back. She agreed.
Documents opened to the tribunal showed that as early as 1987 the blood bank compiled a list of HIV-positive donors who had previously given blood and the dates on which they had previously donated.
On the list was a donor whose blood was given to a Kilkenny healthcare worker in 1985 and who subsequently developed HIV. However, the blood of those on the list was not traced. "I've no doubt it ought to have been done," Dr Lawlor said.
She said there was concern about the effects of telling recipients about possible infection. Mr Durcan said it was paradoxical that donors were told they were HIV positive but recipients were not. Dr Lawlor accepted this.
She said it would have been easier to conduct a look-back at the time as records on the dispatch of blood products to hospitals before 1986 were still available. However, these were shredded in 1993 contrary to instructions of the CEO.
Mr Durcan said the look-back would have been important to prevent infected people infecting others. Dr Lawlor said the greatest risk of onward transmission of HIV was in the first 60 days after exposure to the virus, and a look-back would not have prevented this. Even if people knew they were infected, there was no effective treatment available.
The first look-back began at Pelican House in late 1989 and was initiated by Dr Lawlor. A policy on look-back was not implemented until much later.
Dr Lawlor said she was dismayed in April 1995 when she found a look-back had not been conducted in respect of blood given before HIV screening by five donors who had subsequently tested HIV positive.