Doctors in NI are to receive fresh guidance on how to administer insulin.
The incident happened at Belfast City Hospital four years ago
It follows an inquest into the death of an elderly woman who was given ten times the dose of insulin she needed.
The inquest heard Sarah Smith, 90, from Whiterock Parade in Belfast, became semi-conscious and died after choking on food. It happened four years ago.
The inquest was told it had emerged later that the junior doctor treating her at Belfast City Hospital had not been shown how to measure insulin.
Mrs Smith had not eaten any solid food for more than a week prior to her death.
It is thought that shortly after she ate a piece of food, she regurgitated it back into her gullet and it became trapped in a hiatus hernia she had.
Some time later it passed up her gullet, blocking her voicebox.
As she was semi-conscious, she lost the ability to gag and died within minutes.
The junior doctor, who had been working in his first job for just two weeks, had studied at University College Dublin.
He said afterwards that he had never been shown how to measure insulin.
Evidence at Tuesday's inquest showed it was not clear whether the correct method of administering insulin was spelled out in the hospital's induction day at the time.
Belfast City Hospital also discovered that two other junior doctors trained at UCD were unaware of the correct procedure, the inquest heard.
The hospital informed the Department of Health what had happened.
The department was unable to confirm whether anyone outside Northern Ireland had been told about the incident.
A spokesman said new guidelines would shortly be circulated to all hospitals in the province on, among other matters, how to correctly give insulin.
Belfast Coroner John Leckey said he would also be requesting that the Department of Health take steps to prevent any similar incidents.