Noble's Hospital's pathology department has said sorry for test errors which suggested a Peel man had fatally high levels of an antidepressant in his system.
The apology came at the inquest into the death of Andrew Sharpe.
The 63-year-old was found dead at his home in Ballawattleworth, Peel, on November 24 last year.
An initial post mortem suggested Mr Sharpe died from head injuries sustained when he fell down the stairs at his home.
Tests by the pathology department at Noble's also found a level of Amitriptyline well above that needed to kill someone.
It was subsequently discovered, a couple of months later, that the test was only suitable for determining the presence of such a drug, not the quantity of it.
A letter from the advocate of Mr Sharpe's widow said she felt it was unacceptable such an error had occurred, and she wasn't made aware of it until she contacted the coroner's office in July this year.
Delivering a verdict of accidental death, Coroner of Inquests Jane Hughes offered her condolences to Mr Sharpe's friend and family, particularly his widow.
Mrs Hughes acknowledged the distress had been made worse by the error, and subsequent delays it caused, but said she was satisfied the problem at the lab had been recognised and addressed.
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