On her own admission, it was "hugely significant" information. It may, indeed, have helped to save the lives of a number of haemophiliacs. Yet Dr Paule Cotter, consultant haematologist at Cork University Hospital, kept to herself the discovery in November 1985 that one of her haemophilia B patients had tested positive for HIV.
With hindsight, she said yesterday, it seemed "obvious" that she should have told the Blood Transfusion Service Board and Prof Ian Temperley about the case, as they had no other way of knowing of it.
Apparently, however, it did not occur to her at the time.
Nor did it occur to her to tell anyone the following month of the results of a subsequent test which showed that the patient, given the pseudonym Andrew, had been infected after February 1985. Since Andrew had only received BTSB-made factor 9 from this date, the test proved this product was the source of infection.
Until then, only commercial concentrates had been implicated in the infection of haemophiliacs and treating doctors and the BTSB had been operating on the basis that Irish product was safe.
When exactly Dr Cotter informed Prof Temperley of Andrew's case remains open to debate. Prof Temperley has given evidence to the effect that he was informed sometime after April or May 1986. And this evidence is supported by the fact that he did not include the Cork case in a public lecture he gave in June 1986 about sero-conversions in haemophilia B patients.
The former medical director of the National Haemophilia Treatment Centre has been strongly criticised for his handling of other matters during the infection tragedy. But on this issue his response compares very favourably to Dr Cotter, his treating counterpart in Cork.
As soon as he became aware of the possibility of a link between Pelican House factor 9 and seroconversions, Prof Temperley wrote to the BTSB expressing his concern. He also requested information from regional haemophilia treatment directors and, when he felt the Blood Bank was responding too slowly, he went public with his interim findings - at great risk of facing repercussions from the board.
Dr Cotter, in contrast, failed to circulate data which proved conclusively as early as December 1985 that Irish product could no longer be presumed to be safe.
As the tribunal heard yesterday, she also neglected to initiate a recall of the product implicated in Andrew's infection.
As to when - or whether - she finally told Prof Temperley of the case, Dr Cotter said she could recall speaking to him on the subject - not in December, but sometime afterwards. "I am prepared to accept it was an omission on my part not to do it at the time", she said.
That will come as cold comfort to the six other haemophilia B patients who were infected with HIV, or their next-of-kin. While most of the six are believed to have been infected in 1985 or earlier, one continued to use non-heat-treated BTSB factor 9 up to as late as February 1986.
Three of the six were treated in Dublin, the other three in Drogheda. One passed on the virus to his wife before dying.