A patient recovering from leukaemia died after receiving a blood product contaminated with bacteria, an inquest was told.
Mr Lloyd was having a routine top-up of blood platelets
Undertaker Alan Robert Lloyd, 52, from Prestatyn, who was in remission, was being treated at Glan Clwyd Hospital.
He died last December in the intensive care unit after suffering chest pains, high temperature and tremors.
The coroner, recording an accidental death verdict, said: "Nobody could have known."
The hearing in Prestatyn heard the blood product had come from a National Blood Service centre in Liverpool.
Tests on the bag of platelets later revealed the presence of the bacteria Klebsiella.
Doctors say the bacteria is harmless to healthy people but can infect people with weakened immune systems.
The bug can lead to diseases such as pneumonia, blood poisoning and soft tissue infections.
The inquest on Tuesday heard Mr Lloyd was attending Glan Clwyd every other day for platelet treatment and on 21 December last year he went for a routine check.
Later that day he received a routine top-up of platelets, as he was determined to stay at home over Christmas.
But within 10 minutes he was unwell. After being moved from the clinic to the cardiac unit he was then transferred to the intensive care unit, where he died the next day.
Consultant haematologist Dr Christine Hoyles told the inquest that patients can sometimes react to blood products but in Mr Lloyd's case treatment to counter his symptoms did not work.
Dr Hoyles said she had never before known this infection to come from a platelet transfusion.
She added it was particularly upsetting as Mr Lloyd was in remission against all expectations.
A post-mortem examination found that the cause of Mr Lloyd's death was shock due to the blood contamination.
Recording his verdict, North East Wales coroner John Hughes said Mr Lloyd had shown remarkable resilience in fighting two forms of leukaemia and had high hopes for the future.
He described the case as "a wholly unusual set of affairs" and said he did not want anybody to have the impression it was commonplace.
He added that National Blood Service staff took every care when sending out blood products and that it could not have been anticipated that Mr Lloyd's blood product was contaminated.
Mr Lloyd's widow, Susan Lloyd, who attended the inquest, said her late husband was: "Sadly missed by his friends and family."