Our Lady's Children's Hospital in Crumlin is to review all transcriptions of a cancer gene test after what it believes was a "transcription error" in one case.
The review was confirmed after it emerged that an adult patient was told she did not carry a specific gene that placed her at a higher risk of developing cancer, and later developed ovarian cancer.
The Children's Hospital Group, which oversees operations at the Crumlin hospital, has apologised to the woman involved and said it regrets "the series of events that led to her current difficult situation".
In a statement, it said it believes the case is "an isolated incident caused by human error".
"All facts in this incident currently point to the fact that a transcription error of a genetic test result occurred. This is currently considered to be an isolated incident caused by human error. This fact has been communicated to the woman involved through her treating clinician."
"As a precautionary measure, a review by Our Lady's Children's Hospital, Crumlin is currently underway of all transcriptions of BRACA tests to ensure tests results were transcribed correctly and that no similar transcription error has occurred," said the statement.
The hospital group also said it wished to reassure other patients who have undergone testing that this "is not a testing error and therefore there is no cause for concern or distress".
The Department of Health was notified of the case by the HSE on Friday evening and Minister Simon Harris has been briefed.
He subsequently made contact with the Children's Hospital Group and has been assured that steps are being taken to ensure that the error is not replicated elsewhere.
According to a report in the Ireland edition of the Sunday Times, the woman at the centre of the incident was informed last month that she had tested positive for the BRCA1 gene. She had been told by Our Lady's Children's Hospital in Crumlin in 2009 that she had tested negative.
Someone with the BRCA1 gene is at a higher risk of developing breast or ovarian cancer.
Social Democrats co-leader Róisín Shortall has called on the Minister to instruct the HSE to carry out an audit of women who have been given an all-clear in the same test.
“We need to know how this error happened and how many other women are potentially affected. It’s vital that all women who have undergone the same test are contacted immediately and provided with clear and accurate information about where they stand."
"The Minister for Health and the HSE must move swiftly to review the test results of all women who have undergone BRCA tests at Our Lady’s Children’s Hospital Crumlin in the past decade, to ensure no one else is at risk,” she said.
Ms Shortall said that concerns about standards and resources in the genetics department at Crumlin hospital were criticised in a report by independent experts in 2014.
We need to know what actions, if any, were taken on foot of that report’s findings and recommendations,” she said.